Lighting device

Abstract

According to an aspect of the present invention, there is provided a lighting device (10) comprising: An elongated, concavely shaped reflector (12) defining an elongated reflector cavity (11) and having an open bottom side (12b), wherein the elongated, concavely shaped reflector (12) defines an elastic and / or segmented structure (211) such that the elongated, concavely shaped reflector (12) is bendable in a plane of extension of the open bottom side (12b) from a linear shape to a curved shape; and a row of LEDs (20) arranged inside the cavity (11) along the open bottom side (12b), wherein the LEDs (20) are configured to illuminate a reflective interior surface (12a) of the elongated, concavely shaped reflector (12) such that an output light distribution, formed of light emitted by the row of LEDs (20) and reflected by the reflective interior surface (12a), is emitted from the cavity (11) via the open bottom side (12b); wherein the elongated, concavely shaped reflector (12) is bent to the curved shape, and wherein the lighting device (10) further comprises a support structure (14; 22; 114; 222) disposed along and mechanically coupled to the elongated, concavely shaped reflector (12), wherein the support structure is configured to confer a bending resistance to the elongated, concavely shaped reflector (12) in the curved shape such that the curved shape of the elongated, concavely shaped reflector (12) is maintained.

Description

[0001] Lighting device

[0002] FIELD OF THE INVENTION

[0003] The present invention generally relates to a lighting device.

[0004] BACKGROUND OF THE INVENTION

[0005] There is increasing interest in elongated luminaires with linear and curved sections for use in various lighting applications such as in entrances, lobbies, corridors, conference rooms, dining halls, and other public or representative areas in buildings. Combining luminaires with linear and curved sections allows creating a diversity of architectural shapes. The conventional approach has this far been to manufacture luminaires with fixed shapes using per curve / radii-specific-set tooling, which then may be combined to create more complex shapes.

[0006] SUMMARY OF THE INVENTION

[0007] To enable rational manufacture and deployment, and hence a cost-effective lighting solution, it is thus generally needed to limit the number of fixed shapes to manufacture and stock. However, as realized by the inventors, a limited selection of different luminaire shapes limits the flexibility in designing elongated luminaires. It is thus an object of the present invention to provide a lighting device addressing these drawbacks associated with the conventional approach of forming curved luminaires. These and other objects may be achieved by a lighting device in accordance with the independent claim. Embodiments of the present invention are defined in the dependent claims.

[0008] Hence, according to an aspect of the present invention, there is provided a lighting device comprising: an elongated, concavely shaped reflector defining an elongated cavity with an open bottom side and being formed from an elastic and / or segmented structure such that the concavely shaped reflector is bendable in a plane of extension of the open bottom side from a linear shape to a curved shape; and a row of LEDs arranged inside the cavity along the open bottom side, wherein the LEDs are configured to illuminate a reflective interior surface of the concavely shaped reflector such that an output light distribution, formed of light emitted by the row of LEDs and reflected by the reflective interior surface, is emitted from the cavity via the open bottom side; wherein the lighting device further comprises a support structure disposed along and mechanically coupled to the concavely shaped reflector, wherein the support structure is configured to confer a bending resistance to the concavely shaped reflector once the concavely shaped reflector has been bent to the curved shape such that the curved shape of the concavely shaped reflector is maintained.

[0009] Thus, the present invention is based on an indirectly lit open elongated, concavely shaped reflector, enabling a diffuse output light distribution, which may be bent / deformed from a linear shape (i.e. a straight line shape) to a curved shape. The need for per curve / radii-specific-set bending tooling may hence be avoided while the design flexibility for shaping the lighting device is increased. The cavity thus formed is a single, continuous, elongated cavity being bordered by the reflective interior surface of the elongated, concavely shaped reflector. Said reflective interior surface preferably is (relatively) smooth and continuous, i.e. segmentation thereof is not or hardly visible.

[0010] The term “bendable”, when used in relation to a structure (e.g. the cavity or the support structure), is herein to be understood as “flexibly” bendable in the sense that the structure is bendable or deformable (i.e. upon application of a sufficient bending force) from a linear shape to a curved or bent shape without breaking (e.g. without formation of fissures or cracks in the elongated, concavely shaped reflector). In some embodiments, the bending may be reversible such that the structure may be returned (one or more times) from the bent shape to the initial shape (e.g. the cavity may be returned to the linear shape by flexibly bending the elongated, concavely shaped reflector from the curved shape to the linear shape) and / or a to a further curved shape different from the previous curved shape. The shape of the elongated, concavely shaped reflector being maintained here means that the curved shape of the concavely shaped reflector will not spontaneously change shape (e.g. under forces of gravity), but that the shape of the elongated, concavely shaped reflector can / or will only be changed when additional / extra (external) forces are exerted on the elongated, concavely shaped reflector.

[0011] By the lighting device being based on an indirectly lit open elongated, concavely shaped reflector, the need for providing a diffusive light exit window at the bottom (light exit) side of the cavity is obviated. This further contributes to a rational manufacturing as otherwise a specific exit window needs to be cut from a diffuser sheet for each specific shape of the elongated, concavely shaped reflector. In addition, this process would result in a considerable amount of waste material.

[0012] By providing the elongated, concavely shaped reflector as an elastic and / or segmented structure, the elongated, concavely shaped reflector may be bent from a linear shape to a curved shape without undergoing plastic deformation. An elastic elongated, concavely shaped reflector may be bent into the curved shape while undergoing elastic deformation. A segmented elongated, concavely shaped reflector may be bent into the curved shape without any plastic or elastic deformation. A segmented elongated, concavely shaped reflector may in particular define a floppy structure, implying a substantially zero resistance to bending from the linear shape to the curved shape (and vice versa).

[0013] The elastic and / or segmented structure of the elongated, concavely shaped reflector facilitates bending of the elongated, concavely shaped reflector and, further, facilitates providing the reflective interior surface of the elongated, concavely shaped reflector as a relatively smooth surface also when bent to the curved shape.

[0014] However, the ability of an elastic and / or segmented structure to retain the curved shape may be non-existent or poor. Therefore, the lighting device according to the present invention comprises a support structure for imparting a bending resistance (i.e. bending stiffness) to the elongated, concavely shaped reflector, such that the elongated, concavely shaped reflector may retain the curved shape after being bent thereto. That is, in case the elongated, concavely shaped reflector is elastic, the support structure may be configured to at least offset a restoring force of the cavity. In case the elongated, concavely shaped reflector is segmented and non-elastic (e.g. floppy), the support structure may confer an increased resistance to bending to the elongated, concavely shaped reflector.

[0015] As will become apparent from the following, various embodiments and examples of support structures exist. The increased bend resistance / shape retaining function may for instance be provided by an elongated bend-resistant structure, e.g. comprising a housing enclosing the elongated, concavely shaped reflector and / or a core fixed to the cavity or housing, a stretchable interconnect structure for the LEDs, or a combination thereof.

[0016] As further will become apparent, the support structure (in whole or elements thereof) may be added to the lighting device (i.e. be mechanically coupled to the elongated, concavely shaped reflector) after the elongated, concavely shaped reflector is bent to the curved shape. However, it is also possible that the support structure is present in the lighting device during the bending of the elongated, concavely shaped reflector to the curved shape. In either case, the support structure may be configured to be in equilibrium when the elongated, concavely shaped reflector is in the curved shape such that deviation of the elongated, concavely shaped reflector from the curved shape causes the support structure to impart a restoring force to the cavity for returning the elongated, concavely shaped reflector to the curved shape (i.e. such that the curved shape of the elongated, concavely shaped reflector is maintained).

[0017] Thus, in some embodiments the support structure is bendable in the plane of extension of the open bottom side together with the elongated, concavely shaped reflector, from the linear shape to the curved shape.

[0018] The support structure may thus be configured to allow bending of the elongated, concavely shaped reflector while conferring an increased resistance to bending to the elongated, concavely shaped reflector after the elongated, concavely shaped reflector has been bent to the curved shape.

[0019] In some embodiments, the support structure is configured to undergo plastic deformation when bent together with the elongated, concavely shaped reflector from the linear shape to the curved shape.

[0020] The support structure may thus be deformed together with the elongated, concavely shaped reflector and thus assume a new equilibrium state aligned with the curved shape of the elongated, concavely shaped reflector. A plastic deformation of the support structure will not have any adverse effects on the reflective properties of the elongated, concavely shaped reflector.

[0021] In some embodiments, the support structure comprises an elongated structure extending along and mechanically coupled to the elongated, concavely shaped reflector, wherein the elongated structure is configured to, when the elongated, concavely shaped reflector is in the curved shape, confer a bending resistance to the elongated, concavely shaped reflector such that the curved shape of the elongated, concavely shaped reflector is maintained.

[0022] The elongated structure may thus provide a bend resistance, distributed substantially continuously along the length of the elongated, concavely shaped reflector.

[0023] In some embodiments, the elongated structure comprises an elongated housing with an open bottom side, wherein the elongated, concavely shaped reflector is arranged in the housing.

[0024] The housing may thus act as an outer strong, and bend resistant structure for the inner more easily deformable elongated, concavely shaped reflector providing the reflective interior surface. In some embodiments, the housing is an integrally formed body.

[0025] The housing may hence be formed as a continuous enclosure around the elongated, concavely shaped reflector. The housing may for instance be configured to be bent together with the elongated, concavely shaped reflector, from the linear shape to the curved shape, while undergoing plastic deformation.

[0026] In some embodiments, the housing comprises a plurality of segments pivotably arranged relative each other.

[0027] The housing may hence be formed as a segmented (relatively) hard shell around the elongated, concavely shaped reflector, wherein the segmentation and pivotability facilitates bending of the housing.

[0028] In some embodiments, the elongated structure further comprises an elongated core extending along and being fixed to the elongated, concavely shaped reflector, wherein the core is configured to confer a bending resistance to the elongated, concavely shaped reflector. In embodiments wherein the support structure comprises a housing, the elongated structure may further comprise an elongated core extending along and being fixed to the housing, wherein the core is configured to confer a (further) bending resistance to the housing.

[0029] The elongated support member may for instance be fixed to a top portion of the elongated, concavely shaped reflector or the housing. If the core is fixed to the housing, the bending resistance may be provided to the elongated, concavely shaped reflector via the housing.

[0030] In some embodiments, the row of LEDs are interconnected by a stretchable interconnect structure, wherein the stretchable interconnect structure is configured to, when the elongated, concavely shaped reflector is in the curved shape, confer a bending resistance to the elongated, concavely shaped reflector such that the curved shape of the elongated, concavely shaped reflector is maintained, wherein the stretchable interconnect structure comprises stretchable interconnects that form or form part of the support structure.

[0031] Hence, at least part of the bend resistance may be provided by the stretchable interconnect structure. The stretchable interconnect structure may be fixed to either the elongated, concavely shaped reflector or to the housing (if present). In some embodiments, the lighting device (either the housing or the elongated, concavely shaped reflector) comprises a pair of edge portions extending along opposite sides of the open bottom side, each edge portion having a surface facing an interior of the elongated, concavely shaped reflector, wherein the stretchable interconnect structure is attached to the surface of one of the edge portions. The lighting device may comprise a further row of LEDs interconnected by a further stretchable interconnect structure attached to the surface of the other edge portion.

[0032] In some embodiments, the stretchable interconnect structure comprises a stretchable carrier supporting the row of LEDs.

[0033] The support structure may thus be provided (at least in part) by a stretchable carrier supporting the row of LEDs. The stretchable carrier may be bendable at least in the plane of extension of the open bottom side (which is parallel to the mounting plane of the row of LEDs). The LEDs may be electrically connected by meander-shaped conductive traces formed on the stretchable carrier.

[0034] In some embodiments, the stretchable interconnect structure comprises stretchable wires extending between adjacent LEDs of the row of LEDs.

[0035] The bending resistance of the support structure may thus be provided (at least in part) by stretchable wires extending between respective pairs of LEDs of the row of LEDs.

[0036] In some embodiments, the lighting device comprises a pair of edge portions extending along opposite sides of the open bottom side, each edge portion having a surface facing an interior of the elongated, concavely shaped reflector, wherein the row of LEDs is arranged on the surface of one of the edge portions, and wherein, optionally, the lighting device further comprises a further row of LEDs arranged on the surface of the other edge portion.

[0037] Rows of LEDs may thus be provided along either side of the open bottom side, enabling an improved light output.

[0038] In some embodiments, the elongated, concavely shaped reflector comprises a plurality of pivotably connected segments, wherein each segment extends between a pair of end portions (of the segment), and wherein end portions of adjacent segments overlap.

[0039] This configuration enables a bendable elongated, concavely shaped reflector wherein the bendability derives from the pivotable connection between the successive segments. This allows the elongated, concavely shaped reflector to be shaped with a small bending force. The end portions may slidingly bear against each other such that a frictional force is provided between successive segments. This may provide some degree of bending resistance to the elongated, concavely shaped reflector which may facilitate the shaping (in particular if being shaped before adding the support structure).

[0040] In some embodiments, the elongated, concavely shaped reflector may be bendable only in a plane of extension of the open bottom side, Alternatively, the lighting device may have the feature that it is bendable only in a plane transverse to the plane of extension of the open bottom side. Yet, the lighting device may have the feature that it is bendable in a plane of extension of the open bottom side and also in a plane transverse to the plane of extension of the open bottom side. The elongated, concavely shaped reflector may thus be curved in mutually transverse planes, for example when mounted to a ceiling the elongated, concavely shaped reflector may be bendable in a horizontal and / or vertical plane.

[0041] In some embodiments, the elongated, concavely shaped reflector is bendable to define a radius of curvature of 0.6 meter or less, 0.5 meter or less or 0.4 meter or less. In embodiments wherein the support structure comprises an elongated support structure (e.g. a housing and / or a core), also the support structure may be bendable to define a radius of curvature of 0.6 meter or less, 0.5 meter or less or 0.4 meter or less.

[0042] In some embodiments, a minimum bending force for bending the elongated, concavely shaped reflector from the linear shape to the curved shape is 50 Nm or less, 45 Nm or less, 30 nm or less, or 15 Nm or less. The elongated, concavely shaped reflector (separately, in absence of the support structure) may thus be easily bent by hand, thereby facilitating shaping and installation of the lighting device. The minimum bending force for bending the elongated, concavely shaped reflector here refers to the minimum bending force (i.e. torque) needed to bend the elongated, concavely shaped reflector in absence of the support structure. A lower limit of the minimum bending force may be 0 Nm (e.g. in the case of a segmented elongated, concavely shaped reflector), or 1 Nm or 3 Nm (e.g. in the case of an elastic elongated, concavely shaped reflector).

[0043] In embodiments wherein the support structure is bendable together with the elongated, concavely shaped reflector, from the linear shape to the curved shape, a minimum bending force for bending the elongated, concavely shaped reflector together with the support structure from the linear shape to the curved shape may be in a similar range, i.e. 50 Nm or less, 45 Nm or less, or 30 Nm or less. The elongated, concavely shaped reflector and the support structure may thus be easily bent together by hand, thereby facilitating shaping and installation of the lighting device. In either case, 3 Nm may be a lower limit of the minimum bending force for the elongated, concavely shaped reflector together with the support structure. A somewhat higher minimum bending force (such as 10 Nm) may however enable a more stable shape retaining function. Accordingly, the minimum bending force for bending the elongated, concavely shaped reflector together with the support structure may for instance be in a range from 10-30 Nm, or 10-15 Nm. In some embodiments, a minimum bending force for bending the elongated, concavely shaped reflector and the support structure from the curved shape is at least 3 Nm. That is the bending resistance of the support structure and the elongated, concavely shaped reflector together may be at least 3 Nm.

[0044] BRIEF DESCRIPTION OF THE DRAWINGS

[0045] This and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing embodiments of the present invention.

[0046] Fig. l is a schematic cross-section of a lighting device according to an embodiment.

[0047] Fig. 2 is a perspective view of the lighting device of Fig. 1.

[0048] Fig. 3 shows a stretchable interconnect structure according to an embodiment.

[0049] Fig. 4 shows a support structure comprising a housing and a bendable elongated core according to an embodiment.

[0050] Fig. 5a-c shows a lighting device according to an embodiment.

[0051] Fig. 6 is a perspective view of a lighting device according to an embodiment.

[0052] DETAILED DESCRIPTION

[0053] Fig. 1 schematically shows a schematic cross-section of an embodiment of a luminaire or lighting device 10, across a length dimension of the lighting device 10. The lighting device 10 may be suitable for a ceiling mounted installation, e.g. mounted flush to a ceiling, or in a suspended installation by means of wires, as a few non-limiting examples. Fig. 2 shows the lighting device 10 in a perspective view.

[0054] The lighting device 10 comprises an elongated, concavely shaped reflector 12 with a reflective interior surface 12a and defining an elongated cavity 11 and further having an open bottom side 12b (hereinafter opening 12b) forming an open light exit side of the lighting device 10. The elongated, concavely shaped reflector 12 will typically be open along its full length. That is, the opening 12b may be coextensive with the length dimension of the elongated, concavely shaped reflector 12. The elongated, concavely shaped reflector 12 may as per the illustrated embodiment have an arcuate shape (in cross-section). However, the (cross-sectional) shape of the elongated, concavely shaped reflector 12 is not limited to the specific shape shown in Fig. 1, but may more generally have a cross-sectional shape allowing incident light to be reflected within the cavity 11 by the reflective interior surface 12a of the elongated, concavely shaped reflector 12 towards the opening 12b and be emitted from the cavity 11 via the opening 12b, typically emitted from the cavity 11 only via the opening 12b when the elongated, concavely shaped reflector is highly reflective and fully opaque for light.

[0055] The lighting device 10 further comprises a respective row of LEDs 20 arranged inside the cavity 11, along either side of the opening 12b. The LEDs 20 are configured to illuminate the reflective interior surface 12a of the elongated, concavely shaped reflector 12, wherein the emitted light is reflected by the reflective interior surface 12a to exit the cavity 11 (only) via the opening 12b and thus provide an output light distribution of the lighting device 10. The row of LEDs 20 may be disposed along substantially the full length dimension of the elongated, concavely shaped reflector 12 to provide a continuous, advantageously substantially uniform, distribution of light along the length of the cavity 11 and the lighting device 10. As used herein, the term “LED” is to be understood as encompassing either a single LED emitter, or a cluster of two or more LED emitters (e.g. arranged on a common carrier portion, for instance a cluster of a few surface mounted LED emitters). Accordingly, a row of LEDs may comprise a row of single LED emitters or a row of LED clusters. The element indicated by reference sign 20 may correspondingly schematically represent a single LED emitter or a cluster of LED emitters.

[0056] According to the illustrated embodiment, the lighting device 10 comprises a housing 14 (further described below) comprising a pair of edge portions 16 extending along opposite sides of the open bottom side 12b. Each edge portion 16 has a surface facing an interior of the cavity 11 and each row of LEDs 20 is arranged on the surface of one of the edge portions 16. While in the illustrated embodiment, there is a row of LEDs 20 along either side of the opening 12b it is also possible to provide the lighting device 10 with a row of LEDs 20 along only a single side of the opening 12b.

[0057] The elongated, concavely shaped reflector 12 is formed as an elastic structure such that the elongated, concavely shaped reflector 12 may be flexibly bent from a linear shape to a curved shape. The linear shape may correspond to an initial shape of the elongated, concavely shaped reflector 12, i.e. the shape in which the elongated, concavely shaped reflector 12 is manufactured. The curved shape may correspond to a final shape of the elongated, concavely shaped reflector 12, i.e. the shape to which the elongated, concavely shaped reflector 12 is bent when installed in an environment (e.g. any of the areas mentioned in the background section).

[0058] In order to allow the elongated, concavely shaped reflector 12 to maintain the curved shape, the lighting device 10 further comprises a support structure comprising a housing 14 enclosing the elongated, concavely shaped reflector 12. The elongated, concavely shaped reflector 12 is in other words arranged within the housing 14. The housing 14 is dimensioned such that the elongated, concavely shaped reflector 12 may abut opposite lateral sides of the housing 14. The housing 14 thus forms an elongated structure, extending along and being mechanically coupled to the elongated, concavely shaped reflector 12. The housing 14, like the elongated, concavely shaped reflector 12, has an open bottom side 14b, e.g. coextensive with the opening 12b.

[0059] The housing 14 may be provided with suitably disposed attachment points, such as threaded shafts or holes, hooks, or other conventional types of fixing or gripping arrangements allowing the lighting device 10 to be installed in an environment, for instance being mounted against or suspended from a ceiling. As such arrangements per se are known in the art, these have however been omitted from the drawings to not overly obscure the drawings. The number and spacing of attachment points may in general be dependent on the length and weight of the lighting device 10.

[0060] Fig. 2 shows the lighting device 10, comprising the elongated, concavely shaped reflector 12, defining the cavity 11, and the housing 14, after being bent to a curved shape. The dashed outlines 12’ and 14’ depict the elongated, concavely shaped reflector 12 and the housing 14 respectively in the linear shape, e.g. prior to bending.

[0061] The housing 14 is configured to confer a bending resistance or bending stiffness to the elongated, concavely shaped reflector 12 such that the curved shape of the elongated, concavely shaped reflector 12 is maintained. The housing 14 may be bendable together with the elongated, concavely shaped reflector 12, from the linear shape to the curved shape. The housing 14 may, in contrast to the elongated, concavely shaped reflector 12, undergo plastic deformation when bent from the linear shape to the curved shape and thus be plastically deformed from a first equilibrium state (corresponding to the linear shape) to a second equilibrium state (corresponding to the curved shape). As the reflective interior surface 12a is provided by the elongated, concavely shaped reflector 12, not the housing 14, plastic deformation of the housing 14 does not alter the reflective properties of the reflective interior surface 12a.

[0062] Alternatively, the housing 14 may be bent or pre-formed to a curved shape. The housing 14 may for instance be coupled to the elongated, concavely shaped reflector 12 after the elongated, concavely shaped reflector 12 has been bent to the curved shape, e.g. by inserting the elongated, concavely shaped reflector 12 into the (bent) housing 14 via the open bottom side of the housing 14. By providing the housing 14 with an open end, it is also possible to slidingly insert the elongated, concavely shaped reflector 12 into the bent or preformed housing 14 so that the elongated, concavely shaped reflector 12 assumes a corresponding curved shape, guided by the housing 14.

[0063] The bendable elongated, concavely shaped reflector 12 and the shape retaining supporting housing 14 may be realized in various manners. The elongated, concavely shaped reflector 12 may for instance be formed by an elastic material, e.g. an elastomer such as silicone rubber. The interior surface 12a of the elongated, concavely shaped reflector 12 may be formed as a substantially smooth and diffusively reflective surface. The interior surface 12a may for instance be formed by a reflective coating or film, advantageously with some degree of elasticity such that the reflective properties may be provided also when the elongated, concavely shaped reflector 12 is bent to the curved shape. Some surface structure or topology of the interior surface 12a may be acceptable, provided the topology is below a desired visibility threshold or meet aesthetical requirements for the particular lighting application. To assist in preserving the arcuate cross-sectional shape of the elongated, concavely shaped reflector 12, the elongated, concavely shaped reflector 12 may be formed with arcuate strengthening elements distributed along the elongated, concavely shaped reflector 12. The strengthening elements may for instance be formed by strengthening ribs or corrugations integrally formed with the outer surface of the elongated, concavely shaped reflector 12. Alternatively or additionally, the walls of the elongated, concavely shaped reflector 12 (e.g. of an elastomer) may be reinforced with arcuate metal wires distributed along the elongated, concavely shaped reflector 12, embedded within the wall of the elongated, concavely shaped reflector 12, or adhesively attached to an outer surface of the elongated, concavely shaped reflector 12.

[0064] As the housing 14 forms a structure distinct from the elongated, concavely shaped reflector 12, the housing 14 may generally be formed with a composition and a structure so as to provide the desired shape retaining function, with less regard to its optical and reflective properties (as those are provided by the elongated, concavely shaped reflector 12).

[0065] The housing 14 may be formed as an integrally formed body, e.g. of a plastic material such as polyurethane. By choosing the material thickness of the housing 14 in view of the resilience of the material forming the housing 14, the housing 14 may be adapted to confer a desired amount of bending resistance to the elongated, concavely shaped reflector 12. In case the housing 14 is configured to be bent together with the elongated, concavely shaped reflector 12, a minimum bending force for bending the elongated, concavely shaped reflector 12 together with the housing 14 from the linear shape to the curved shape may be 50 Nm or less, 45 Nm or less, or 30 Nm or less (thus easily bendable by hand), for instance 10- 30 Nm or 10-15 Nm. A minimum bending force for bending the elongated, concavely shaped reflector 12 together with the housing 14 from the curved shape to the linear shape (i.e. returning the elongated, concavely shaped reflector 12 and the housing 14 to the linear shape) may be in a similar range, e.g. 50 Nm or less, such as 10-30 Nm or 10-15 Nm. A minimum bending force for bending only the elastic elongated, concavely shaped reflector 12 (i.e. separately from the housing 14) from the linear shape to the curved shape may be 50 Nm or less, 45 Nm or less, or 30 Nm or less, such as in a range of 1-30 Nm or 3-15 Nm. In any case, the minimum for bending only the elongated, concavely shaped reflector 12 may be less than the minimum bending force for bending the elongated, concavely shaped reflector 12 together with the housing 14. If the housing 14 is pre-formed to the curved shape, a minimum bending force for bending the housing 14 may be greater, for instance such that bending by hand is impractical. The housing 14 may then be formed of sheet metal, e.g. aluminum, and bent using bending tools.

[0066] In either case, the housing 14 may after being bent to, or if pre-formed, to the desired curved shape, confer a bending resistance to the elongated, concavely shaped reflector 12 so as to at least balance any possible elastic restoring force of the elongated, concavely shaped reflector 12 striving to return the cavity from the curved shape to the linear shape.

[0067] As may be appreciated, the specific curved shape shown in Fig. 2 is merely a non-limiting example and many other curved shapes are possible. In Fig. 2, the elongated, concavely shaped reflector 12 (and the housing 14) are bent in a plane of extension of the opening 12b, corresponding to the horizontal plane H indicated in Fig. 2. The elongated, concavely shaped reflector 12 (and the housing 14) may for example be bendable to define a curved shape, in the horizontal plane H, with a radius of curvature of 0.6 meter or less, 0.5 meter or less or 0.4 meter or less, e.g. depending on the shaping requirements of the particular lighting application. A length of the elongated, concavely shaped reflector 12 (and the housing 14) may be such that, for a given radius of curvature, a bending angle of up to + / - 90° may be achieved. Greater bending angles may be achieved by adding two or more cavities in succession.

[0068] In Fig. 2, the radius of curvature is substantially constant. Fig. 6 depicts a corresponding lighting device 310 comprising sections 310a, 310b, 310c with different radius of curvature. As exemplified in Fig. 6, the lighting device 310 may comprise a combination of curved (310a, 310c) and linear (310b) sections.

[0069] While reference in the above has been made to the housing 14 defining the support structure, the shape retaining support function need not be provided solely by the housing 14, but provided by additional structures or elements.

[0070] With reference to Fig. 3 there is shown a stretchable interconnect structure 22 interconnecting the LEDs of each row of LEDs 20 (i.e. the row of single LED emitters or row of cluster of LED emitters). The interconnect structure 22 may provide power and control signals to the LEDs 20. The stretchable interconnect structure 22 comprises a stretchable carrier 18 supporting the row of LEDs 20 and stretchable wires such as meander-shaped conductive traces (dashed lines in Fig. 3) extending between and electrically interconnecting the LEDs 20. The stretchable carrier 18 may be bendable at least in the plane of extension of the opening 12b, i.e. the horizontal plane H which is parallel to the mounting plane of the row of LEDs 20. The stretchable carrier 18 may as shown in Fig. 1 be attached to the surface of the edges 16 of the housing 14, e.g. by an adhesive, rivets, screws or the like.

[0071] The stretchable interconnect structure 22 is configured to, when the elongated, concavely shaped reflector 12 is in the curved shape, together with the housing 14, confer a bending resistance to the elongated, concavely shaped reflector 12 such that the curved shape of the elongated, concavely shaped reflector 12 is maintained. The stretchable interconnect 22 may thus form part of the support structure together with the housing 14. The stretchable interconnect structure 22 may in analogy with the housing 14 be bent together with the elongated, concavely shaped reflector 12 from the linear shape to the curved shape, or be added to the lighting device 10 after bending the elongated, concavely shaped reflector 12. In any case, the stretchable interconnect structure 22 may be arranged to be in an equilibrium state when the elongated, concavely shaped reflector 12 is in the curved shape such that a deviation of the elongated, concavely shaped reflector 12 from the curved shape causes the interconnect structure 22 to impart a restoring force to the elongated, concavely shaped reflector 12 for returning the elongated, concavely shaped reflector 12 to the curved shape. The preceding discussion of the minimum bending resistance of the housing 14 applies correspondingly to a support structure defined by the housing 14 and the stretchable interconnect structure 22. For instance, in case both the housing 14 and the stretchable interconnect structure 22 of the support structure is configured to be bent together with the elongated, concavely shaped reflector 12, a minimum bending force for bending the elongated, concavely shaped reflector 12 together with the housing 14 and interconnect structure 22 from the linear shape to the curved shape may be in a range from 10-30 Nm or 10-15 Nm. A minimum bending force for returning the elongated, concavely shaped reflector 12 and the support structure to the linear shape may be in a similar range. According to a further option, the housing 14 may be configured to be bendable together with the elongated, concavely shaped reflector 12, while the interconnect structure 22 may be configured to be added to the lighting device 10 after bending. The interconnect structure 22 may thus confer a further increased bending resistance to the housing 14 and thus the elongated, concavely shaped reflector 12. A minimum bending force for returning the elongated, concavely shaped reflector 12 and the support structure to the linear shape after adding the interconnect structure 22 may thus exceed the minimum bending force for returning only the elongated, concavely shaped reflector 12 and the housing 14 to the linear shape.

[0072] Fig. 4 depicts a support structure according to another embodiment comprising a housing 114 comprising a plurality of segments 1141 pivotably arranged relative each other, and a bendable elongated core 1142 connecting the segments 1141. The core 1142 extends along the length direction of the housing 114 and is attached to each segment 1141, e.g. by an adhesive or by fixing members such as staples straddling the core 1142. The core 1142 is configured to confer an increased resistance to bending to the housing 114 such that the core 1142 together with the housing 114 may define an elongated support structure conferring a bending resistance to the elongated, concavely shaped reflector 12.

[0073] The support structure of Fig. 4 may be configured to be bent together with the elongated, concavely shaped reflector 12 from the linear shape to the curved shape. The core 1142 may thus be bent together with the housing 114 and the elongated, concavely shaped reflector 12. The core 1142 may be configured to undergo plastic deformation when bent to the curved shape. The core 1142 may be formed with a cylindrical shape. The core 1142 may for instance be formed of metal, such as iron. The core 1142 may advantageously, like the elongated, concavely shaped reflector 12, be configured to be bendable by hand force (e.g. by a minimum bending force of 50 Nm or less, such as 10-30 Nm or 10-15 Nm). However, the housing 114 and the core 1142 may also be preformed to the curved shape, wherein a minimum bending force for bending the core 1142 (and thus the support structure) may be greater, for instance such that bending by hand is impractical.

[0074] Adjacent segments 1141 of the housing 114 may be arranged with an overlap. Each segment 141 may for instance as shown comprise a narrow end portion 1141a extending into a subsequent segment 1141. A cross sectional dimension of the end portion 1141a may be such that there is a play or gap between an outer surface of the end portion 1141a and an inner surface of the receiving portion of the subsequent segment, thereby allowing successive segments to be pivoted relative each other. For example, the outer surface of the end portion 1141a may be sloping relative the inner surface of the receiving portion of the subsequent segment, along at least part of the circumference of the segment 1141a. Providing the slope along the mutually opposite sidewalls of the segment 1141a allows the segments 1141 to be pivoted, and thus the housing 114 to be bent, in a plane of extension of the opening 12b of the elongated, concavely shaped reflector 12. According to a further example, the end portions 1141a may be flexible.

[0075] The cross-sectional view of the lighting device 10 in Fig. 1 may generally also be representative of a cross-section of a lighting device comprising the housing 114. Thus, the elongated, concavely shaped reflector 12 (not visible in Fig. 4) may like in the view of Fig. 1 be arranged within the housing 114, and the housing 114 may be dimensioned such that the elongated, concavely shaped reflector 12 may abut opposite lateral sides of the housing 114. The housing 114 may hence be formed as a segmented (relatively) hard shell around the elongated, concavely shaped reflector 12. The segments 1141 may be formed by a plastic material or by metal, such as aluminum.

[0076] Each segment may comprise a pair of edge portions on opposite sides of the opening 12b of the elongated, concavely shaped reflector 12 (corresponding to the edge portions 16 in Fig. 1) for supporting a respective LED (e.g. a respective single LED emitter or a respective cluster of LED emitters) of a row of LEDs. Each LED (single LED emitter or cluster of LED emitters) may be supported by a respective carrier portion, and each LED may be interconnected by a stretchable interconnect structure comprising stretchable wires extending between the LEDs of the respective segments 1141 (e.g. like the wires 2221 in Fig. 5b, discussed below). The stretchable bundles may thus further contribute to the bend resistance of the overall support structure.

[0077] Fig. 5a-c depict a lighting device 210 according to a further embodiment. The lighting device 210 comprises a elongated, concavely shaped reflector 212 forming the border of a cavity 11, which elongated, concavely shaped reflector 212, rather than being defined as an elastic structure, is defined as a bendable segmented structure 211. Fig. 5a shows a schematic cross-section of a representative segment 2121 of the segmented structure 211 of the elongated concavely shaped reflector212 and the lighting device 210. Fig. 5b shows a partial sideview of the lighting device 210, along an edge 216 of the elongated, concavely shaped reflector 212. Fig. 5c shows a schematic top-down view of the lighting device 210. The segmented structure 211 of the elongated concavely shaped reflector 212 comprises a plurality of pivotably connected segments 2121. Each segment 2121 may as shown in Fig. 5a comprise a pair of edge portions 2161 arranged on opposite sides of the open bottom side 212b. The edge portions 2161 of the segments 2121 may thus collectively define a pair of common edge portions 216 of the elongated, concavely shaped reflector 212. A respective row of LEDs 220 may be supported by one or each edge portion 216 of the elongated, concavely shaped reflector 212. In line with the preceding discussion it is to be understood that each LED 220 here may refer either to a single LED emitter or to a cluster of LED emitters. The LEDs 220 may, as shown in Fig. 5b-c, be arranged along the elongated, concavely shaped reflector 212 at a pitch corresponding to a pitch of the segments 2121, such that a respective LED 220 (a single LED or a cluster of LEDs) is arranged on a respective edge portion 2122 of each segment 2121. In other words, a pitch of the LEDs 220 of a row (i.e. a pitch of the single LED emitters or the clusters of LED emitters of the row) may correspond to a pitch of the segments 2121.

[0078] Each segment 2121 has a reflective interior surface such that the segments 2121 of the elongated, concavely shaped reflector 212 collectively define a reflective interior surface 212a. Each segment 2121 has an open bottom side such that the segments 2121 of the elongated, concavely shaped reflector 212 collectively define an open bottom side or opening 212b of the elongated, concavely shaped reflector 212 and the lighting device 10. Each segment 2121 may as shown have an arcuate shape, and more generally be shaped to allow incident light from the one or two rows of LEDs 220 of the lighting device 210 to be reflected within the cavity 11 by the reflective interior surface 212a, and towards the opening 212b.

[0079] Each segment 2121 extends between a pair of end portions of the segment 2121, and end portions of adjacent segments overlap to define an un-interrupted interior reflective surface 212a. As indicated in Fig. 5b-c, every other segment 2121 may have a smaller cross-sectional dimension than the other segments 2121 such that every other segment 2121 may be received in a successive larger-cross sectional dimension segment 2121. A play or gap may be provided between an outer surface of each smaller cross- sectional dimension segment and an inner surface of the subsequent receiving larger-cross sectional dimension segment 2121, to allow successive segments to be pivoted relative each other, at least in a plane of extension of the opening 212b of the elongated, concavely shaped reflector 212. This configuration hence enables a bendable elongated, concavely shaped reflector 212 wherein the bendability derives from the pivotable arrangement of successive segments 2121. This allows the elongated, concavely shaped reflector 212 to be bent upon application of a small bending force. The end portions of successive segments 2121 may optionally be arranged to slidingly bear against each other such that a frictional force is provided between successive segments 2121. This may provide some degree of inherent bending resistance to the cavity 2121, which may facilitate the shaping (in particular if being shaped before adding the support structure). In absence of any substantial frictional force between successive abutting segments 2121, the elongated, concavely shaped reflector 212 may in define a floppy structure (e.g. corresponding to a minimum force for bending the elongated, concavely shaped reflector 12 being substantially zero).

[0080] As shown in Fig. 5b-c, the LEDs 220 of each row may be interconnected by a stretchable interconnect structure 222, comprising stretchable bend-resistant wires 2221 extending between adjacent LEDs 220 of each row of LEDs. More specifically, each LED 220 (e.g. single LED emitters or clusters of LED emitters) of a row of LEDs may be arranged on a respective discrete carrier portion, wherein the carrier portions are sequentially connected by the stretchable and bend-resistant wires 2221. The stretchable interconnect structure 222 may thus be configured to define a support structure of the lighting device 210, conferring a bending resistance to the bendable elongated, concavely shaped reflector 212, such that the elongated, concavely shaped reflector 212 may retain a curved shape after being bent thereto.

[0081] The wires 2221 may as shown be arranged to extend in an arcuate shape between successive segments 2121 (and thus successive LEDs 220 and carrier portions). A separation between successive segments 2121 may thus be increased or decreased, wherein the respective connecting wires 2221 may stretch (i.e. by increasing the radius of curvature of the arcuate shape of the wires) or compress (i.e. by decreasing the radius of curvature of the arcuate shape of the wires). The wires may be arranged to be in equilibrium when the elongated, concavely shaped reflector 212 is in the curved shape such that a deviation of the elongated, concavely shaped reflector 212 from the curved shape causes the wires 2221 to impart a restoring force to the elongated, concavely shaped reflector 212 for returning the elongated, concavely shaped reflector 212 to the curved shape. In analogy with the above discussion of the stretchable interconnect structure 22, the stretchable wires 2221 may be arranged in the elongated, concavely shaped reflector 212 when the elongated, concavely shaped reflector 212 is in the linear shape, and thus be bent together with the elongated, concavely shaped reflector 212 to the desired curved shape. The stretchable wires 2221 may in this case be configured to undergo plastic deformation to assume a new equilibrium state corresponding to the curved shape of the elongated, concavely shaped reflector 212. Alternatively, the stretchable wires 2221 may be added to the elongated, concavely shaped reflector 212 after bending thereof to the desired curved shape.

[0082] It is further possible to supplement the segmented elongated, concavely shaped reflector 212 in Fig. 5a-c with a bendable elongated core such as the core 1142 shown in Fig. 4. The core 1142 may thus supplement or replace the stretchable interconnect structure 222 as the support structure for the elongated, concavely shaped reflector 212. Accordingly, the support structure of the lighting device 210 may (further) comprise an elongated core extending along and being fixed to the elongated, concavely shaped reflector 212, and being configured to confer a (further) bending resistance to the elongated, concavely shaped reflector 212. In this case, the stretchable wires 2221 may, but need not, contribute to the bending resistance of the support structure.

[0083] While the above discussion mainly has been concerned with bending of an elongated, concavely shaped reflector (e.g. 12 and 212) in a horizontal plane H, a cavity may additionally, or alternatively, be configured to be bendable in a vertical plane. Bending in the vertical plane will now by way of example be discussed with reference to Fig. 2, however the discussion is applicable also to the embodiments of the housing 114 and the lighting device 210. With reference to Fig. 2, the elongated, concavely shaped reflector 12 may be bendable in the vertical plane denoted V, i.e. transverse to the plane of extension of the opening 12b. The elongated, concavely shaped reflector 12 may for instance be bendable from a linear shape to a curved shape in the vertical plane V. The elongated, concavely shaped reflector 12 may be bendable to define a curved shape in the vertical plane V with a radius of curvature and bending angle in the same ranges as discussed above with reference to the horizontal plane H. It is contemplated that in some lighting applications, the elongated, concavely shaped reflector 12 may however need to accommodate less degree of bending in the vertical plane V than in the horizontal plane H. For instance, the elongated, concavely shaped reflector 12 may be bendable by up to + / - 90° in the horizontal plane H, and only (+ / -) 10-30° in the vertical plane V. In any case, the support structure may be configured to provide a bending resistance not only in the horizontal plane H, but also in the vertical plane V, such that the curved shape of the elongated, concavely shaped reflector 12 may be maintained in both the horizontal plane H and the vertical plane V. In line with the preceding discussion, in the case of bending the elongated, concavely shaped reflector 12 also in the vertical plane V, the support structure may additionally be configured to confer a bending resistance to the elongated, concavely shaped reflector 12 in the vertical plane V, so as to at least balance any possible elastic restoring force of the elongated, concavely shaped reflector 12 in the vertical plane V, and further any gravitational force acting to deform the elongated, concavely shaped reflector 12 from the desired curved shape in the vertical plane V.

[0084] The person skilled in the art realizes that the present invention by no means is limited to the embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims.

Claims

CLAIMS:

1. A lighting device (10) comprising: an elongated, concavely shaped reflector (12) defining an elongated cavity (11) and having an open bottom side (12b) and being formed from an elastic and / or segmented structure (211) such that the concavely shaped reflector is bendable in a plane of extension of the open bottom side (12b) from a linear shape to a curved shape; and a row of LEDs (20) arranged inside the cavity (11) along the open bottom side (12b), wherein the LEDs (20) are configured to illuminate a reflective interior surface (12a) of the concavely shaped reflector (12) such that an output light distribution, formed of light emitted by the row of LEDs (20) and reflected by the reflective interior surface (12a), is emitted from the cavity (11) via the open bottom side (12b); wherein the lighting device (10) further comprises a support structure (14; 22; 114; 222) disposed along and mechanically coupled to the concavely shaped reflector, wherein the support structure is bendable together with the elongated, concavely shaped reflector (12), from the linear shape to the curved shape, and wherein the support structure is configured to confer a bending resistance to the concavely shaped reflector (12) once the concavely shaped reflector has been bent to the curved shape, such that the curved shape of the concavely shaped reflector (12) is maintained.

2. The lighting device according to claim 1, wherein the support structure is configured to undergo plastic deformation when bent together with the elongated, concavely shaped reflector (12) from the linear shape to the curved shape.

3. The lighting device according to any one of claims 1-2, wherein the support structure comprises an elongated structure (14) extending along and mechanically coupled to the elongated, concavely shaped reflector (12), wherein the elongated structure (14) is configured to, when the elongated, concavely shaped reflector (12) is in the curved shape, confer a bending resistance to the elongated, concavely shaped reflector (12) such that the curved shape of the elongated, concavely shaped reflector (12) is maintained.

4. The lighting device (10) according to claim 3, wherein the elongated structure comprises an elongated housing (14) with an open bottom side (14b), wherein the elongated, concavely shaped reflector (12) is arranged in the housing (14).

5. The lighting device (10) according to claim 4, wherein the housing (14) is an integrally formed body.

6. The lighting device (110) according to claim 4, wherein the housing (114) comprises a plurality of segments (1141) pivotably arranged relative each other.

7. The lighting device according to any one of claims 3-6, wherein the elongated structure further comprises an elongated core (1142) extending along and being fixed to the elongated, concavely shaped reflector (12), or when dependent on any one of claims 4-6, the housing (114), wherein the core is configured to confer a bending resistance to the elongated, concavely shaped reflector (12) or the housing (114).

8. The lighting device according to any one of the preceding claims, wherein the row of LEDs (20) are interconnected by a stretchable interconnect structure (22; 222), wherein the stretchable interconnect structure comprises stretchable interconnects and is configured to, when the elongated, concavely shaped reflector (12) is in the curved shape, confer an increased resistance to bending to the elongated, concavely shaped reflector (12) such that the curved shape of the elongated, concavely shaped reflector (12) is maintained, wherein the stretchable interconnects form or form part of the support structure.

9. The lighting device according to claim 8, wherein the stretchable interconnect structure (22) comprises a stretchable carrier (18) supporting the row of LEDs (20).

10. The lighting device according to claim 8, wherein the stretchable interconnect structure (222) comprises stretchable wires (2221) extending between adjacent LEDs of the row of LEDs (220).

11. The lighting device (110) according to any one of the preceding claims, wherein the elongated, concavely shaped reflector (212) comprises a plurality of pivotablyconnected segments (2121), wherein each segment extends between a pair of end portions, and wherein end portions of adjacent segments overlap.

12. The lighting device (110) according to any one of the preceding claims, wherein the elongated, concavely shaped reflector (12) is bendable in a plane transverse to the plane of extension of the open bottom side (12b).

13. The lighting device (110) according to any one of the preceding claims, wherein the elongated, concavely shaped reflector (12; 212), and when dependent on claim 2 also the housing (14), is bendable to define a radius of curvature of 0.6 meter or less, 0.5 meter or less or 0.4 meter or less.

14. The lighting device (110) according to any one of the preceding claims, wherein a minimum bending force for bending the elongated, concavely shaped reflector (12) from the linear shape to the curved shape is 50 Nm or less, 45 Nm or less, 30 Nm or less, or 15 Nm or less, or, wherein the support structure is bendable together with the elongated, concavely shaped reflector (12), from the linear shape to the curved shape, and wherein a minimum bending force for bending the elongated, concavely shaped reflector (12) together with the support structure from the linear shape to the curved shape is 50 Nm or less, 45 Nm or less, 30 Nm or less, or 15 Nm or less.

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