FIELD OF THE INVENTION

The present invention relates to a luminaire for road surface illumination comprising solid state lighting elements.

The present invention further relates to a solid state lighting (SSL) assembly for use in such a luminaire.

BACKGROUND OF THE INVENTION

With a continuously growing population, it is becoming increasingly difficult to meet the world's energy needs as well as to kerb greenhouse gas emissions that are considered responsible for global warming phenomena. These concerns have triggered a drive towards a more efficient use of energy, such as reduced electricity consumption.

One of the drivers behind the efforts to reduce electricity consumption is the introduction of more energy-efficient lighting. A particular promising alternative is provided by solid state lighting (SSL) devices, which can produce a unit luminous output at a fraction of the energy cost of incandescent light bulbs. An example of such a SSL element is a light emitting diode. A drawback of SSL element-based lighting devices is that individual SSL elements have a much lower luminous output than e.g. incandescent, tungsten halogen or fluorescent light bulbs, such that it is necessary to include multiple SSL elements in a single lighting device to obtain the required luminous output levels.

A particularly interesting application domain is road surface illumination. It is well-known that such illumination, e.g. illumination of roads, public spaces such as parking lots, motorways, pavements, train station platforms and so on, comes at a considerable energy cost. Light bulb lifetime is also important in such application domains as maintenance of the road surface illumination device may be cumbersome and costly, such that bulb failure should be postponed for as long as possible. SSL devices address many of these concerns through their excellent lifetime and modest energy consumption. However, it is not straightforward to provide a road surface illumination device with sufficient luminous output using SSL elements. In addition, the Lambertian light intensity distribution produced by SSL elements is quite different to traditional light bulbs, which raises concerns about glare. Such glare effects are unwanted on roads as it can blind drivers, thus compromising road safety.

WO 201 1/051542 A1 discloses an illuminator for illuminating road surfaces having a SSL element as a light source and a reflector for reflecting the light produced by the SSL element towards the road surface. The luminous surface of the SSL element is directed away from the road surface and the reflector is mounted over the luminous surface to reflect the luminous output of the SSL element towards the road surface such that the road surface is indirectly illuminated only. The reflective element has a reflecting surface comprising at least one planar cut or a portion of a planar cut, which ensures a substantially homogeneous light intensity on the area of the road surface to be illuminated.

However, it is not trivial in this arrangement to achieve a high luminous output. In particular, because of the indirect illumination arrangement, the heat sink for the SSL elements has to be located in between the SSL elements and the road surface to be illuminated, which limits the available area of the heat sink due to the fact that the reflected luminous output has to pass the heat sink. The limitations to the heat sink design limit the amount of heat the SSL elements can produce. This therefore limits the achievable luminous output of such an illuminator.

SUMMARY OF THE INVENTION

The present invention seeks to provide a luminaire for road surface illumination capable of producing a high luminous output.

The present invention further relates to a SSL assembly for use in such a luminaire.

According to an aspect of the present invention, there is provided a luminaire for road surface illumination, the luminaire comprising a housing including a light exit area and a support structure opposite the light exit area; a first solid state lighting assembly mounted on the support structure, the assembly comprising a first assembly member mounted on the support structure; a plurality of first carriers mounted on the first assembly member and having a first main surface and an opposite second main surface extending from said first assembly member towards the light exit area; a plurality of first solid state lighting elements, wherein the first main surface of each first carrier carries at least one of said first solid state lighting elements, said at least one of said first solid state lighting elements being arranged to emit light at least in a first direction perpendicular to said first main surface; and a plurality of first reflective members mounted in said housing, each first reflective member having a reflective surface facing a first main surface of one of said first carriers for reflecting at least a part of the luminous output of the at least one first solid state lighting element on said first main surface.

Such a luminaire benefits from the fact that the SSL assembly is located above the luminous surfaces of the SSL elements, such that it does not interfere with the luminous output of the SSL elements onto the road surface through the light exit area facing the road surface in normal use of the luminaire. Consequently, a large size heat sink can for instance be integrated into the luminaire, which facilitates the use of a higher density and/or higher intensity SSL elements, thus increasing the luminous output intensity of the luminaire.

Moreover, because the luminous surfaces of the SSL elements produce a Lambertian light distribution having its symmetry axis (the first direction) parallel to the road surface in normal use of the luminaire, the reflective element can be shaped to allow a portion of the luminous output to pass the reflective element and directly illuminate the road surface. Not only does this avoid the loss of luminous output for a portion of this output due to the fact that absorption of the luminous output by the reflective element is avoided, this furthermore can be used to create a non-symmetrical luminous distribution such that a road user approaching the luminaire in the intended direction is confronted with a lower light intensity than a road user moving away from the luminaire following this intended direction. Preferably, the first assembly member comprises a first heat sink member such that the heat sink member can be used to mount the SSL assembly in the housing. This limits the amount of components of the SSL assembly, thus reducing manufacturing cost.

Alternatively, the first solid state lighting assembly further comprises a first heat sink member mounted on the second main surface of each first carrier.

The first reflective members may be mounted on the first assembly member. This embodiment provides a compact and easy to manufacture luminaire, which reduces its cost of production.

The first heat sink member may comprise a first surface on which the plurality of first carriers is mounted and a second surface extending from the first surface, the luminaire further comprising a first driver circuit mounted on said second surface for driving at least some of the first solid state lighting elements. Consequently, this provides a modular luminaire including a SSL assembly module comprising the heat sink member, SSL element carriers and driver circuits for the SSL elements. This facilitates the easy replacement of the SSL assembly module in the luminaire, thus improving the ease of maintenance of the luminaire.

In an embodiment, the luminaire further comprises a plurality of second solid state lighting elements, wherein the second main surface of each first carrier carries at least one of said second solid state lighting elements, said at least one of said second solid state lighting elements being arranged to emit light at least in a second direction perpendicular to said second main surface; and a plurality of second reflective members mounted in said housing, each second reflective member having a reflective surface facing a second main surface of one of said first carriers for reflecting at least a part of the luminous output of the at least one second solid state lighting on said second main surface.

This produces a luminaire capable of a particularly high luminous output as both surfaces of the carrier in line with the road surface in normal use of the luminaire carry SSL elements. Consequently, a much higher number of SSL elements can be integrated into the luminaire compared to the illumination device disclosed in WO 201 1/051542 A1 .

The second reflective members may be mounted on the first assembly member to provide a compact and easy to manufacture luminaire, which reduces its cost of production.

In case of the first assembly member comprising a first heat sink member, the first heat sink member may comprise a first surface on which the plurality of first carriers is mounted and a third surface opposite a second surface extending from the first surface, the luminaire further comprising a second driver circuit mounted on said third surface for driving at least some of the second solid state lighting elements. Consequently, this provides a modular luminaire including a SSL assembly module comprising the heat sink member, SSL element carriers and driver circuits for the SSL elements. This facilitates the easy replacement of the heat sink assembly module in the luminaire, thus improving the ease of maintenance of the luminaire.

In accordance with yet another embodiment, the luminaire further comprises a second SSL assembly mounted on said support structure, said second SSL assembly comprising a second assembly member mounted on the support structure; a plurality of second carriers mounted on the second assembly member and having a further first main surface and an opposite further second main surface extending from said second assembly member towards the light exit area, wherein the respective first main surfaces of the first carriers and the respective further first main surfaces of the second carriers are oriented in the same direction; a plurality of second solid state lighting elements, wherein the further second main surface of each second carrier carries at least one of said second solid state lighting elements, said at least one of said second solid state lighting elements being arranged to emit light at least in a second direction perpendicular to said further second main surface; and a plurality of second reflective members mounted in said housing, each second reflective member having a reflective surface facing a further second main surface of one of said second carriers for reflecting at least a part of the luminous output of the at least one second solid state lighting element on said further second main surface.

This provides an alternative solution to increasing the number of SSL elements in the luminaire and therefore its luminous output. Due to the fact that the heat sinks do not interfere with the luminous output of the SSL elements, multiple heat sinks that take up a significant volume of the (upper part of the) luminaire may be used.

Each first reflective member may be placed adjacent to a second reflective member in a back-to-back orientation. Alternatively, the reflective surface of each first reflective member may face the reflective surface of a second reflective member, i.e. the first reflective member may be placed relative to a second reflective member in a face-to-face orientation.

The second reflective members may be mounted on the second heat sink member to provide a compact and easy to manufacture luminaire, which reduces its cost of production.

The second SSL assembly member may comprise a second heat sink member comprising a further first surface on which the plurality of second carriers is mounted and a further second surface extending from the further first surface, the luminaire further comprising a second driver circuit mounted on said further second surface for driving at least some of the second solid state lighting elements. Consequently, this provides a modular luminaire including a heat sink assembly module comprising the heat sink member, SSL element carriers and driver circuits for the SSL elements. This facilitates the easy replacement of the heat sink assembly module in the luminaire, thus improving the ease of maintenance of the luminaire.

In an embodiment, each of the first reflective members is arranged to create a first light distribution profile from the luminous output of the at least one of the first solid state lighting elements; each of the second reflective members is arranged to create a second light distribution profile from the luminous output of one of the second solid state lighting elements; and the first light distribution profile is different to the second light distribution profile. This facilitates the generation of a non-symmetrical luminous distribution by the luminaire such that a road user approaching the luminaire in the intended direction is confronted with a lower light intensity than a road user moving away from the luminaire following this intended direction, thereby reducing the risk of the road user being blinded by the luminaire.

In yet another embodiment, the luminaire further comprises a plurality of third solid state lighting elements, wherein the further first main surface of each second carrier carries at least one of said third solid state lighting elements, said at least one of said third solid state lighting elements being arranged to emit light at least in a first direction perpendicular to said further first main surface; a plurality of third reflective members mounted in said housing, each third reflective member having a reflective surface facing a further first main surface of one of said second carriers for reflecting at least a part of the luminous output of the at least one third solid state lighting element on said further first main surface; a plurality of fourth solid state lighting elements, wherein the second main surface of each first carrier carries at least one of said fourth solid state lighting elements, said at least one of said fourth solid state lighting elements being arranged to emit light at least in a second direction perpendicular to said second main surface; and a plurality of fourth reflective members mounted in said housing, each fourth reflective member having a reflective surface facing a second main surface of one of said first carriers for reflecting at least a part of the luminous output of the at least one fourth solid state lighting element on said second main surface.

By having multiple heat sink assemblies in the luminaire with each heat sink assembly comprises carriers having opposite luminous surfaces, a luminaire with a particularly high luminous output is provided.

According to another aspect of the present invention there is provided a SSL assembly for mounting on the support structure of the luminaire according to one or more embodiments of the present invention, the SSL assembly comprising an assembly member; a plurality of first carriers mounted on the assembly member, each of said first carriers having a first main surface and an opposite second main surface extending from said assembly member; a plurality of first solid state lighting elements, wherein the first main surface of each first carrier carries at least one of said first solid state lighting elements, said at least one of said first solid state lighting elements being arranged to emit light at least in a first direction perpendicular to said first main surface; and a first driver circuit. Such an assembly can be used to repair luminaires in which one ore more of the SSL elements have failed. This therefore avoids having to replace the whole luminaire, thereby reducing the maintenance cost.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are described in more detail and by way of non-limiting examples with reference to the accompanying drawings, wherein:

FIG. 1 schematically depicts a cross-section of a luminaire according to an embodiment of the present invention;

FIG. 2 schematically depicts a side view of an aspect of the luminaire of

FIG. 1 ;

FIG. 3 shows a light distribution plot of the luminaire of FIG. 1 ;

FIG. 4 schematically depicts the luminaire of FIG. 1 fitted over a road surface;

FIG. 5 schematically depicts a cross-section of a luminaire according to another embodiment of the present invention;

FIG. 6 schematically depicts a light distribution profile of the luminaire of

FIG. 5;

FIG. 7 shows a light distribution plot of the luminaire of FIG. 5;

FIG. 8 shows a light distribution plot of a luminaire according to an alternative embodiment;

FIG. 9 schematically depicts a perspective view of the luminaire of FIG. 5;

FIG. 10 schematically depicts a cross-section of a luminaire according to yet another embodiment of the present invention;

FIG. 11 schematically depicts a cross-section of a luminaire according to yet another embodiment of the present invention; FIG. 12 schematically depicts a cross-section of a luminaire according to yet another embodiment of the present invention;

FIG. 13 schematically depicts a perspective view of the luminaire of FIG.

10;

FIG. 14 schematically depicts a perspective view of the luminaire of FIG.

1 1 ;

FIG. 15 schematically depicts a perspective view of the luminaire of FIG. 12; and

FIG. 16 schematically depicts a perspective view of a luminaire according to yet another embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

It should be understood that the Figures are merely schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the Figures to indicate the same or similar parts.

FIG. 1 schematically depicts a luminaire 100 for road surface illumination. The luminaire 100 comprises a housing 1 12 including a light exit area 1 14. The housing 1 12 may be made of any suitable material, e.g. a suitable metal or metal alloy, a suitable polymer, a combination of such suitable materials and so on. The light exit area 1 14 may be an opening in the housing 1 12 or may be a removable part of the housing 1 12 through which light can escape the luminaire 100. The light exit area 1 14 may for instance be transparent or translucent. In an embodiment, the light exit area 1 14 may comprise one or more optical elements, e.g. diffusers, lenses or micro-lenses to shape the luminous output of the luminaire 100. Alternatively, the light exit area 1 14 may be free of such optical elements. The light exit area may be made of any suitable material, e.g. a transparent or translucent polymer such as polycarbonate or PMMA.

The housing 112 comprises a support structure for mounting an SSL assembly as will be explained in more detail later. In an embodiment, the support structure comprises an inner rim or lip 1 16 to which support struts 1 18 are fixed. The support struts 1 18 may be permanently fixed to the inner rim 1 16, e.g. through gluing, soldering, welding or the like, or may be removably fixed to the inner rim 1 16, e.g. screwed to the inner rim 1 16. The support struts 1 18 extend across the luminaire 100 between opposite portions of the inner rim 1 16. The support struts 1 18 may be made of any suitable material. Preferably the support struts 1 18 are made of a metal or metal alloy to exploit the favourable heat conduction properties of such materials. It should be understood that the particular embodiment of the support structure shown in FIG. 1 is a mere design choice and that any suitable support structure may be included in the housing 1 12.

The luminaire 100 further comprises a SSL assembly mounted on the support structure of the housing 1 12. To this end, the SSL assembly comprises a first assembly member mounted on the support struts 1 18. In the embodiment shown in FIG. 1 , the first assembly member comprises a first heat sink member 120. A side view of the SSL assembly is schematically depicted in FIG. 2. The assembly member of the heat sink assembly comprises a first heat sink member 120 supported by the support struts 1 18. The first heat sink member 120 is typically made of a heat conducting material, such as a metal or metal alloy. A plurality of first carriers 130 is mounted on a first surface of the first heat sink member 120. The first surface of the heat sink member 120 is the surface of the heat sink member 120 facing the light exit area 1 14. The first carriers 130 each have a first main surface 132 and an opposite second main surface 134 extending from the first surface of the first heat sink member 130 towards the light exit area 1 14.

The first heat sink member 120 may comprise a plurality of cooling fins 122 on a further surface opposite the first surface on which the carriers 130 are mounted to increase the surface area of the first heat sink member 120, thereby improving the heat transfer from the first heat sink member 120 to the surrounding medium, e.g. air, as is known per se.

The SSL assembly further comprises a plurality of first SSL elements 140, wherein the first main surface 132 of each first carrier 130 carries at least one of the first SSL elements 140. The first SSL elements 140 are arranged to emit light at least in a first direction perpendicular to the first main surfaces 132 of the first carriers 130 on which the first SSL elements are mounted. In an embodiment, each first carrier 130 carrying one or more first SSL elements 140 is a chip-onboard (COB) in which the SSL element chip is directly attached to the first carrier 130. As is known per se, this enables a higher density of first SSL elements 140 per unit area of the first carrier 130, thus facilitating a more intense luminous output per unit area of the first carrier 130.

The luminaire 100 further comprises a plurality of first reflective members 150 mounted in the housing 1 12. Each first reflective member 150 has a reflective surface facing a first main surface 132 of one of said first carriers 130 such that at least a part of the luminous output of the at least one first SSL element 140 on the first main surface 132 is redirected towards a road surface through the light exit area 1 14 of the housing 1 12. This is shown in FIG. 1 by the arrow originating from the at least one first SSL element 140. The dashed part of this arrow indicates the reflected portion of the luminous output of the at least one first SSL element 140. This ensures that at least a portion of the luminous output of the first SSL elements 140 illuminates a road surface in an indirect fashion. In an embodiment, the portion of the luminous output of the first SSL element(s) 140 reflected by the first reflective element 150 is a majority portion of the luminous output of the first SSL element(s) 140.

The first reflective element 150 may have any suitable reflective surface, such as a freeform reflective surface or a faceted reflective surface. A faceted reflective surface is more easily manufactured, in particular if the first reflective element 150 is formed from a metal or metal alloy. The first reflective element 150 may have any suitable shape or form, e.g. a metal reflector or mirror.

In an embodiment, the first reflective elements 150 are mounted on the first assembly member, e.g. on the first heat sink member 120. The first reflective elements 150 may be removably mounted on the first assembly member, e.g. the first heat sink member 120, e.g. clipped, screwed or secured in any other suitable manner, such that the first reflective elements 150 can be removed from the first assembly member, e.g. the first heat sink member 120, e.g., when the first SSL assembly is to be replaced. Alternatively, the first reflective elements 150 may form an integral part of the first SSL assembly such that the first reflective elements 150 cannot be disconnected from the first assembly member, e.g. the first heat sink member 120. In another embodiment, the first reflective elements 150 may be mounted on another part of the luminaire 100, e.g. on part of the housing 1 12.

The first SSL assembly further comprises one or more first driver circuits 160 for driving the first SSL elements 140. The first driver circuits 160 may be mounted in any suitable location in the luminaire 100, such as on the first assembly member, e.g. on a side surface of the first heat sink member 120 by way of non-limiting example, e.g., on a second surface of the first heat sink member 120 that extends from the first surface of the first heat sink member 120 on which the first carriers 130 are mounted. It should be understood that the one or more first driver circuits 160 may be mounted on any suitable surface of the luminaire 100 such as on any suitable surface of the first SSL assembly, e.g. any further surface of the first heat sink member 120.

FIG. 3 depicts a light distribution plot of the luminaire 100 of FIG. 1 relative to a road direction shown in FIG. 4. The luminaire 100 produces a first light distribution 200 in a direction opposite to the intended direction of travel over the road 10 and a second light distribution 300 in the intended direction of travel over the road 10. The luminaire 100 is placed alongside the road 10 such that the first direction in which the first SSL elements 140 generate their luminous output is anti-parallel to the intended direction of travel over the road 10. In other words, the portion of the luminous output of the first SSL elements 140 that is not reflected by the first reflective elements 150 is responsible for the light distribution 200 whereas the portion of the luminous output of the first SSL elements 140 reflected by the first reflective elements 150 is responsible for the light distribution 300.

The luminaire 100 produces an asymmetric light distribution in which the minor light distribution 200 is created by direct illumination of the surface of the road 10 and the major light distribution 300 is created by indirect illumination of th e surface of the road 10. A road user travelling in the intended direction over the road 10 will face the minor light distribution 200 is created by direct illumination of the surface of the road 10. Due to the low intensity of this light, the risk of the road user being confronted with glare is reduced. The majority of light produced by the luminaire 100 is directed away from the road user, i.e. is directed along his direction of travel, such that the road user will not directly face the source of this light, i.e. first SSL elements 140, also because the major light distribution 300 is created by indirect illumination of the surface of the road 10, i.e. is reflected onto the road surface 10 by the first reflective elements 150.

It is noted that this does not necessarily cause an uneven illumination of the road 10. If the luminaires 100 on the road 10 are suitably spaced apart, the majority light distribution 300 of an upstream luminaire 100 will overlap with the minority light distribution 200 of a downstream luminaire 100, such that the combined luminous outputs creates a substantially homogeneous illumination pattern on the road 10. For instance, it is known per se that up to five luminaires may position on the same side of the road 10 such that their luminous outputs overlap to create a homogeneous light distribution on the road surface. It should be understood that the luminaires according to embodiments of the present invention may be placed along a road 10 to create any suitable light distribution, e.g. a linear distribution, an S-distribution, a Z-distribution and so on. The latter distributions may for instance be chosen to create a homogenous light distribution if luminaires are placed on both sides of the road.

It should furthermore be understood that it is equally feasible to create the minor light distribution 200 by indirect illumination of the surface of the road 10 and create the major light distribution 300 by direct illumination of the surface of the road 10. This for instance can be achieved by placing the luminaire 100 such that the first SSL elements 140 generate light in the intended direction of travel over the road 10, thereby creating the luminous distribution 300, whereas the first reflective elements 150 are shaped such that a minority fraction of the luminous output of the first SSL elements 140 is redirected in the opposite direction, thereby creating the luminous distribution 200. In this embodiment a road user never directly faces the luminous surface of one of the first SSL elements 140, this further reducing the risk of the road user being temporarily blinded by the luminous output of such a surface.

FIG. 5 schematically depicts a cross-section and FIG. 9 schematically depicts a perspective view of a luminaire 500 according to another embodiment of the present invention. The luminaire 500 comprises the same features as the luminaire 100, which features have been identified by the same reference numerals and have already been described in detail in the detailed description of FIG. 1 such that the description of the features shared by luminaires 100 and 500 will not be repeated for the sake of brevity.

The luminaire 500 further comprises a plurality of second SSL elements 240 on the second main surfaces 134 of the first carriers 130. The SSL elements 240 preferably are LEDs. Each second main surface 134 of the first carriers 130 carries at least one of said second SSL elements 240. The second SSL elements are arranged to emit light at least in a second direction perpendicular to the second main surface 134. As will be readily understood, the second direction is opposite to the first direction in which the SSL elements 140 produce their luminous output.

The luminaire 500 further comprises a plurality of second reflective members 250 mounted in the housing 1 12. Each second reflective member 250 has a reflective surface facing a second main surface 134 of one of the first carriers 130 such that at least a part of the luminous output of the at least one second SSL element 240 on the second main surface 132 of the first carrier 130 is redirected towards a road surface through the light exit area 1 14 of the housing 1 12.

The second reflective elements 250 may have any suitable reflective surface, such as a freeform reflective surface or a faceted reflective surface. A faceted reflective surface is more easily manufactured, in particular if the second reflective elements 250 are formed from a metal or metal alloy. The second reflective elements 250 may have any suitable shape or form, e.g. a metal reflector or mirror. In an embodiment, the second reflective elements 250 are mounted on the first assembly member, e.g. the first heat sink member 120. The second reflective elements 250 may be removably mounted on the first assembly member, e.g. the first heat sink member 120, e.g. clipped, screwed or secured in any other suitable manner, such that the second reflective elements 250 can be removed from the first assembly member, e.g. the first heat sink member 120, e.g., when the first SSL assembly is to be replaced. Alternatively, the second reflective elements 250 may form an integral part of the first SSL assembly such that the second reflective elements 250 cannot be disconnected from the first assembly member, e.g. the first heat sink member 120. In another embodiment, the second reflective elements 250 may be mounted on another part of the luminaire 100, e.g. on part of the housing 1 12.

The first SSL assembly may further comprise one or more second driver circuits 260 for driving the second SSL elements 240. The second driver circuits 260 may be mounted on the first assembly member, e.g. on a side surface of the first heat sink member 120 by way of non-limiting example, e.g., on a third surface of the heat sink member 120 that extends from the first surface of the first heat sink member 120 on which the first carriers 130 are mounted. The third surface may be opposite to the second surface. It should be understood that the one or more second driver circuits 260 may be mounted on any suitable surface of the first SSL assembly, e.g. any further surface of the first heat sink member 120.

In an embodiment, the second reflective elements 250 are the mirror image of the first reflective elements 150. Alternatively, the second reflective elements 250 may have the same shape as the first reflective elements 150.

The luminaire 500 may be designed to produce a luminous output as shown in FIG. 6-8. As shown in FIG. 6, the first reflective elements 150 and the second reflective elements 250 may be arranged such that part of the luminous output of the first SSL elements 140 and second SSL elements 240 respectively mainly is reflected to an area as indicated by the dashed lines in FIG. 6, whereas th e solid lines indicate the direct illumination produced by the luminaire 500 along the direction of travel.

FIG. 7 and 8 depict the luminous intensity produced by the luminaire 500 along the direction of travel. As can be seen in FIG. 7, the luminaire 500 may generate a symmetrical luminous distribution along the direction of travel, such that a road user is confronted with the same amount of light when approaching the luminaire 500 as when moving away from the luminaire 500. This also produces a homogeneous illumination of the road surface, such that the perception of dark spots in between luminaires 500 on the road 10 can be avoided.

It should however be understood that it is equally feasible to produce an asymmetric light distribution along the direction of a pavement or road 10 as shown in FIG. 3 with the luminaire 500. This may for instance be achieved by a difference in power between the first SSL elements 140 on the one hand and the second SSL elements 240 on the other hand, and/or by first reflective elements 150 having a different shape and/or a different optical power than the second reflective elements 250. Such asymmetric embodiments may for instance be used to create a lower intensity light distribution 200 in the direction opposite or anti-parallel to the intended direction of travel of the road user and a higher intensity light distribution 300 along this intended direction of travel, thereby reducing the risk of the road user being exposed to glare as previously explained. A light distribution in accordance with this embodiment is shown in FIG. 8.

In other words, each of the first reflective members 150 is arranged to create a first light distribution profile from the luminous output of the at least one of the first solid state lighting elements 140 and each of the second reflective members 250 is arranged to create a second light distribution profile from the luminous output of at least one of the second solid state lighting elements 240, wherein the first light distribution profile is different to the second light distribution profile.

It is furthermore noted that an asymmetric light distribution may also be produced by the luminaire 500 in the direction perpendicular to the direction (of travel) of the road 10. This for instance can be achieved by appropriately shaping the first reflective elements 150 and the second reflective elements 250, i.e. by giving the first reflective elements 150 and the second reflective elements 250 a suitable asymmetric shape. Such an asymmetric light distribution may for instance be beneficial to shield a pavement or walkway adjacent to the road 10 from becoming too brightly lit, which can impair the vision of pedestrians on this pavement or walkway.

FIG. 10 schematically depicts a cross-section and FIG. 13 schematically depicts a perspective view of a luminaire 600 according to another embodiment of the present invention. The luminaire 600 comprises the same features as the luminaire 500, which features have been identified by the same reference numerals and have already been referred to in the detailed description of FIG. 5 such that the description of the features shared by luminaires 500 and 600 will not be repeated for the sake of brevity.

The luminaire 600 differs from the luminaire 500 in that the luminaire 600 comprises a further SSL assembly comprising comprises a second assembly member for mounting the second SSL assembly on the support structure of the housing 1 12. In an embodiment, the second assembly member comprises a second heat sink member 220 supported by the support struts 1 18. The second heat sink member 220 is typically made of a heat conducting material, such as a metal or metal alloy.

A plurality of second carriers 230 is mounted on the second assembly member, e.g. on the second heat sink member 220. It will be understood that the first surface of the first heat sink member 120 and the first surface of the second heat sink member 220 both face the light exit area 1 14 and preferably lie in the same plane. The second carriers 230 each have having a further first main surface and an opposite further second main surface extending from the second assembly member, e.g. from the second heat sink member 220 towards the light exit area 1 14. The respective first main surfaces 132 of the first carriers and the respective further first main surfaces of the second carriers 230 are oriented in the same direction, i.e. face the same way. The second heat sink member 220 may also comprise a plurality of cooling fins on a further surface opposite the first surface on which the second carriers 230 are mounted to increase the surface area of the second heat sink member 220, thereby improving the heat transfer from the second heat sink member 220 to the surrounding medium, e.g. air, as is known per se.

Whereas in the luminaire 500 the second SSL elements 240 are located on the second main surface 134 of the first carrier 130, in the luminaire 600 the second SSL elements 240 are located on the further second main surfaces of the second carriers 230 and are arranged to emit light at least in a second direction perpendicular to the further second main surfaces of the first carriers 230 on which the second SSL elements 240 are mounted. In an embodiment, each second carrier 230 carrying one or more second SSL elements 240 is a chip-onboard (COB) in which the SSL element chip is directly attached to the second carrier 230.

The second reflective elements 250 may be mounted on the second assembly member, e.g. on the second heat sink member 220. The second reflective elements 250 may be removably mounted on the second assembly member, e.g. on the second heat sink member 220, e.g. clipped, screwed or secured in any other suitable manner, such that the second reflective elements 250 can be removed from the second assembly member, e.g. from the second heat sink member 220, e.g., when the further SSL assembly is to be replaced. Alternatively, the second reflective elements 250 may form an integral part of the further SSL assembly such that the second reflective elements 250 cannot be disconnected from the second assembly member. In another embodiment, the second reflective elements 250 may be mounted on another part of the luminaire 100, e.g. on part of the housing 1 12.

The further heat sink assembly further comprises one or more second driver circuits 260 for driving the second SSL elements 240. The second driver circuits 260 may be mounted on the second assembly member, e.g. on a side surface of the second heat sink member 220 by way of non-limiting example, e.g., on a second or third surface of the heat sink member 120 that extends from th e first surface of the first heat sink member 120 on which the first carriers 130 are mounted. The third surface may be opposite to the second surface. It should be understood that the one or more second driver circuits 260 may be mounted on any suitable surface of the SSL assembly, e.g. any further surface of the second heat sink member 220.

In an embodiment, the second reflective elements 250 are the mirror image of the first reflective elements 150. Alternatively, the second reflective elements 250 may have the same shape or may have a different as the first reflective elements 150. As already explained in the context of FIG. 9, the first reflective elements 150 and the second reflective elements 250 may cooperate to form a symmetrical or an asymmetrical light distribution along the direction of a road 10.

The design of the luminaire 600 may for instance be used in case the first SSL elements 140 and the second SSL elements 240 are high power SSL elements such that the heat generated by the first SSL elements 140 and the second SSL elements 240 respectively may overheat a single carrier such as the first carrier 130 and/or a single heat sink member such as the first heat sink member 120. The additional heat dissipation capacity provided by the second heat sink member 220 thus facilitates a luminaire 600 with increased luminous power.

In FIG. 10 the first reflective elements 150 and the second reflective elements 250 are arranged respective to each other in a face-to-face arrangement; i.e. the respective reflective surfaces of the first reflective elements 150 and the second reflective elements 250 face each other. However, it should be understood that it is equally feasible to have the first reflective elements 150 and the second reflective elements 250 arranged in an orientation where the first reflective elements 150 and the second reflective elements 250 are arranged respective to each other in a back-to-back arrangement. A cross-section of this embodiment is schematically shown in FIG. 1 1 and a perspective view of this embodiment is schematically shown in FIG. 14. Apart from the fact that the first SSL assembly and the further SSL assembly are mirror-images in the luminaire 700, the luminaire 700 otherwise is identical to the luminaire 600 such that the luminaire 700 will not be described in further detail for the sake of brevity.

FIG. 12 schematically depicts a cross-section and FIG. 15 schematically depicts a perspective view of a luminaire 800 according to yet another embodiment of the present invention.

The luminaire 800 comprises the same features as the luminaire 700, which features have been identified by the same reference numerals and have already been referred to in the detailed description of FIG. 1 1 such that the description of the features shared by luminaires 700 and 800 will not be repeated for the sake of brevity.

The luminaire 800 further comprises a plurality of third SSL elements 340, wherein the further first main surface of each second carrier 230 carries at least one of said third SSL elements. The at least one of said third SSL elements 340 is arranged to emit light at least in a first direction perpendicular to said further first main surface. In an embodiment, the third SSL elements 340 are LEDs.

The luminaire 800 further comprises a plurality of third reflective members 350 mounted in said housing 1 12, wherein each third reflective member 350 has a reflective surface facing a further first main surface of one of the second carriers 230 for reflecting at least a part of the luminous output of the at least one third solid state lighting element 350 on the further first main surface. In an embodiment, the third reflective elements 350 may be mounted on the second assembly member, e.g. on the second heat sink member 220. The third reflective elements 350 may be removably mounted on the second assembly member, e.g. on the second heat sink member 220, e.g. clipped, screwed or secured in any other suitable manner, such that the third reflective elements 350 can be removed from the second assembly member, e.g. on the second heat sink member 220, e.g., when the further SSL assembly is to be replaced. Alternately, the third reflective elements 450 may be integrated in the further SSL assembly as explained before.

The luminaire 800 further comprises a plurality of fourth SSL elements 440, wherein the second main surface 134 of each first carrier 130 carries at least one of said fourth SSL elements 440. The at least one of said fourth SSL elements 440 is arranged to emit light at least in a second direction perpendicular to the second main surface 134. In an embodiment, the fourth SSL elements 440 are LEDs.

The luminaire 800 further comprises a plurality of fourth reflective members 450 mounted in said housing, wherein each fourth reflective member has a reflective surface facing a second main surface 134 of one of the first carriers 130 for reflecting at least a part of the luminous output of the at least one fourth solid state lighting element 440 on said second main surface. In an embodiment, the fourth reflective elements 450 may be mounted on the first assembly member, e.g. on the first heat sink member 120. The fourth reflective elements 450 may be removably mounted on the first assembly member, e.g. on the first heat sink member 120, e.g. clipped, screwed or secured in any other suitable manner, such that the fourth reflective elements 450 can be removed from the first assembly member, e.g. from the first heat sink member 120, e.g., when the first SSL assembly is to be replaced. Alternately, the fourth reflective elements 450 may be integrated in the first SSL assembly as explained before.

The luminaire 800 may further a third driver circuit 360 for driving at least some of the third SSL elements 340 and a fourth driver circuit for driving at least some of the third SSL elements 440. The third driver circuit 360 may be mounted on an available surface of the second heat sink member 220 and the fourth driver circuit 460 may be mounted on an available surface of the first heat sink member 120.

As will have been understood from the previously disclosed embodiments of the luminaire of the present invention, the first reflective elements 150, the second reflective elements 250, the third reflective elements 350 and the fourth reflective elements 450 may have individually selected shapes, i.e. may all have the same shape or may have different shapes, e.g. the first reflective elements 150 may have the same shape as the third reflective elements 350 and the second reflective elements 250 may have the same shape as the fourth reflective elements 450. The first reflective elements 150 and the third reflective elements 350 may be the mirror-image of the second reflective elements 250 and the fourth reflective elements 450. Consequently, the luminaire 800 may be designed to produce a symmetrical or an asymmetrical light distribution profile as previously explained.

The design of the luminaire 800 may for instance be used in case the first SSL elements 140 and the second SSL elements 240 are medium power SSL elements such that the heat generated by the first SSL elements 140 and the second SSL elements 240 respectively can be dissipated by a single carrier such as the first carrier 130 and/or a single heat sink member such as the first heat sink member 120. The additional luminous power provided by the second SSL assembly thus facilitates a luminaire 800 with increased luminous power compared to the luminaire 500 in which only a single SSL assembly is present.

In the previous embodiments, the assembly member of the SSL assemblies in the luminaire 100 comprises a heat sink member such as the first heat sink member 120 and the second heat sink member 220. However, it should be understood that other embodiments of such an assembly member are equally feasible. This is schematically demonstrated in FIG. 16, in which the first heat sink assembly is mounted to a support strut 1 18 of the support structure in the housing 1 12 of the luminaire 900 via an assembly member 125 in the form of a support bar or strip.

In this embodiment, the first heat sink member 120 is mounted onto the second main surface of the first carrier 130, with one or more first SSL elements 140 being present at the first main surface of the first carrier 130 and arranged to direct their luminous output towards the first reflective element 150. A first driver circuit 160 may be mounted on a further surface of the first assembly member 125 that is opposite to the first surface of the first assembly member 125 from which the carriers 130 extend. In this embodiment, the first carriers 130 carry SSL elements on only one main surface, with the opposite main surface carrying the first heat sink 120.

It should be understood that the luminaire 900 is shown to comprise a single SSL assembly by way of non-limiting example only. Multiple SSL assemblies may be present in the luminaire 900. Generally, the teachings of the present invention may be extended to luminaires in which more than two SSL assemblies are present.

In summary, in at least some embodiments of the present invention, a modular luminaire is provided in which one or more replaceable SSL assembly modules are present that may be mounted on the support structure in the housing 1 12 of these luminaires. It should be understood that the SSL assemblies described in relation to the respective luminaires 100, 500, 600, 700 800 and 900 may all be produced and marketed as separate stand-alone entities that for instance can be used to repair luminaires according to embodiments of the present invention or even be retro-fitted into existing luminaires.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps other than those listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several distinct elements. In the device claim enumerating several means, several of these means can be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.