Wall washer luminaire

Abstract

A wall washer luminaire (100, 200, 300), comprising: a linear light source (350) extending in a first direction (X) and lying in a first plane (X-Z); a reflector arrangement (120, 220, 320) forming a curved reflective surface configured to reflect light emitted by the linear light source, wherein the first plane intersects the curved reflective surface such that the light source is contained within a volume delimited by the curved reflective surface, and the curved reflective surface has an overall concave shape that is curved in any plane that intersects the curved reflective surface; and a barrier (360) configured such that only light reflected by the reflector arrangement (120, 220, 320) is output by the wall washer luminaire.

Description

[0001] WALL WASHER LUMINAIRE

[0002] FIELD OF THE INVENTION

[0003] The invention relates to the field of wall washer luminaires.

[0004] BACKGROUND OF THE INVENTION

[0005] Wall washer luminaires are designed to illuminate a surface (e.g. a wall or poster), and are used in a wide range of applications, including in shops, restaurants, art galleries, etc.

[0006] Existing wall washer luminaires often provide illumination with poor uniformity, and many existing wall washer luminaires have low efficiency.

[0007] There is an ongoing desire to provide improved wall washer luminaires.

[0008] US 5800050A discloses downlight and downlight wall wash reflectors particularly useful with compact fluorescent lamps and other large-area light sources, the reflector optics of the invention maximize the efficiency of the luminaire while providing brightness control and avoidance of high angle glare or "flash".

[0009] SUMMARY OF THE INVENTION

[0010] The invention is defined by the claims.

[0011] According to examples in accordance with an aspect of the invention, there is provided a wall washer luminaire, comprising: a linear light source extending in a first direction and lying in a first plane; and a reflector arrangement forming a curved reflective surface configured to reflect light emitted by the linear light source, wherein the first plane intersects the curved reflective surface such that the light source is contained within a volume delimited by the curved reflective surface, and the curved reflective surface has an overall concave shape that is curved in any plane that intersects the curved reflective surface.

[0012] This arrangement provides a more uniform light distribution on a surface illuminated by the wall washer luminaire, and a higher light output ratio, than existing wall washer luminaires. In some examples, the wall washer luminaire further comprises a barrier configured such that only light reflected by the reflector arrangement is output by the wall washer luminaire.

[0013] In other words, light emitted by the linear light source is prevented from directly exiting the wall washer luminaire by the barrier, thus reducing glare.

[0014] In some examples, the curved reflective surface is symmetric with respect to a second plane, perpendicular to the first direction.

[0015] In some examples, an axis defining a greatest distance from the first plane to the curved reflective surface in a second direction perpendicular to the first plane has a non-zero offset from the linear light source; a third plane, containing the axis and parallel to the first direction, virtually divides the reflector arrangement into two halves, wherein an edge of the half containing the linear light source lands on the first plane.

[0016] This ensures that light emitted by the linear light source does not leak from the edge of the half of the reflector arrangement containing the linear light source.

[0017] In some examples, the reflector arrangement comprises a plurality of reflective elements. In other words, the curved reflective surface may be a faceted surface. This further improves a uniformity of the light distribution, and reduces glare.

[0018] In some examples, each reflective element has a radius of curvature of less than 50 mm. This improves a smoothness of light on any wall extending around a comer.

[0019] In some examples, the reflector arrangement consists of a continuous curved reflective surface.

[0020] In some examples, an angle of the barrier with respect to a normal of the first plane is in the range of 10-30°.

[0021] In some examples, the angle of the barrier with respect to the normal of the first plane is in the range of 15-20°. This further improves the uniformity of light distribution and the light output ratio.

[0022] In some examples, a surface of the barrier on which light emitted by the linear light source is incident is a reflective surface. This further improves the light output ratio of the wall washer luminaire.

[0023] In some examples, the wall washer luminaire further comprises a mounting element for mounting the wall washer luminaire to a track.

[0024] In some examples, the wall washer luminaire further comprises a housing configured for recess mounting. In some examples, a greatest distance from the first plane to an edge of the reflector arrangement in a second direction perpendicular to the first plane is less than a greatest distance from the first plane to the reflector arrangement in the second direction.

[0025] The greatest distance from the plane in which the linear light source lies to an edge of the reflector arrangement defines a size of a light output window of the wall washer luminaire. If this distance is less than the overall greatest distance from the plane in which the linear light source lies to the reflector arrangement, glare is reduced.

[0026] In some examples, the curved reflective surface has a reflectivity of at least 85%.

[0027] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment s) described hereinafter.

[0028] BRIEF DESCRIPTION OF THE DRAWINGS

[0029] For a better understanding of the invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, in which:

[0030] Figure 1 illustrates a wall washer luminaire, according to an embodiment of the invention;

[0031] Figure 2 illustrates a wall washer luminaire, according to another embodiment of the invention;

[0032] Figure 3 illustrates a cross-sectional view of a wall washer luminaire, according to yet another embodiment of the invention;

[0033] Figure 4 illustrates a perspective view of the reflector arrangement of the wall washer luminaire of Figure 3;

[0034] Figure 5 illustrates a sectional view of the wall washer luminaire of Figure 3; and

[0035] Figure 6 illustrates an exploded view of the wall washer luminaire of Figure 3.

[0036] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] The invention will be described with reference to the Figures.

[0038] It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the apparatus, systems and methods, are intended for purposes of illustration only and are not intended to limit the scope of the invention. These and other features, aspects, and advantages of the apparatus, systems and methods of the present invention will become better understood from the following description, appended claims, and accompanying drawings. 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.

[0039] The invention provides a wall washer luminaire comprising a linear light source and a reflector arrangement. The linear light source extends in a first direction and lies in a first plane. The reflector arrangement forms a curved reflective surface configured to reflect light emitted by the linear light source. The curved reflective surface has an overall concave shape, and is curved in any plane that intersects the curved reflective surface. The first plane intersects the curved reflective surface, such that the curved reflective surface bounds a volume in which the linear light source is provided.

[0040] Illustrative embodiments may, for example, be employed in indoor lighting systems, such as warehouse lighting systems and retail lighting systems.

[0041] Figure 1 illustrates a wall washer luminaire 100, according to an embodiment of the invention. The wall washer luminaire comprises a linear light source (not visible in Figure 1) and a reflector arrangement 120 that forms a curved reflective surface configured to reflect light emitted by the linear light source. The linear light source and reflector arrangement are described in more detail below.

[0042] In Figure 1, the wall washer luminaire 100 further comprises a housing 110 containing the linear light source. The reflector arrangement 120 may form part of the housing (i.e. a non-reflective surface of the reflector arrangement may form an outer surface of the housing, with the curved reflective surface forming an inner surface of the housing). The housing defines a window 115 to allow light to exit the wall washer luminaire. An outer surface of the housing may have a low reflectivity (such as a reflectivity less than 10%, e.g. a reflectivity of 5%).

[0043] The wall washer luminaire 100 of Figure 1 further comprises a mounting element 140, attached to the housing, for mounting the wall washer luminaire to a track 10. In some examples, the wall washer luminaire may further comprise a heatsink 130. In Figure 1, the linear light source is provided between the heatsink and the reflector arrangement 120. In some examples, the heatsink may have a reflective surface (e.g. with a reflectivity of at least 85%).

[0044] Figure 2 illustrates a wall washer luminaire 200, according to another embodiment of the invention. The wall washer luminaire 200 is similar to the wall washer luminaire 100 described above with respect to Figure 1, comprising a linear light source (not visible in Figure 2) and a reflector arrangement 220, but is configured for recess mounting instead of track mounting. In particular, the wall washer luminaire 200 comprises a housing 210 configured for recess mounting.

[0045] Figure 3 illustrates a cross-sectional view of a wall washer luminaire 300, according to yet another embodiment of the invention. The wall washer luminaire 300 comprises a linear light source 350 and a reflector arrangement 320 that forms a curved reflective surface configured to reflect light emitted by the linear light source.

[0046] The linear light source 350 extends in a first direction X and lies in a first plane X-Z. The linear light source may, for example, comprise a plurality of LEDs (e.g. provided on a printed circuit board, PCB).

[0047] The first plane X-Z intersects the curved reflective surface of the reflector arrangement 320, such that the linear light source is provided within a volume bound by the curved reflective surface. The curved reflective surface has an overall concave shape across the entire surface (such that there are no inflection points in the overall shape of the curved reflective surface), and is curved in any plane that intersects the curved reflective surface (in other words, the curved reflective surface is curved in two directions). In other words, the curved reflective surface has a positive (non-zero) Gaussian curvature. In some examples, the curved reflective surface of the reflector arrangement 320 is symmetric with respect to a second plane Y-Z that is perpendicular to the first direction X.

[0048] The curved reflective surface of the reflector arrangement 320 may have a reflectivity of at least 85% (e.g. reflectivity of 89%). The reflector arrangement may be made from any suitable material for providing the desired reflectivity; for instance, the reflector arrangement may be made from plastic with vacuum aluminium plating to provide the curved reflective surface.

[0049] In Figure 3, an axis Yi defining a greatest distance from the first plane X-Z to the curved reflective surface in a second direction Y perpendicular to the first plane (i.e. a distance from the first plane to a peak in the curved reflective surface) has a non-zero offset from the linear light source 350. A third plane X-Yi, containing the axis Yi and parallel to the first direction X, virtually divides the reflector arrangement 320 into two halves (i.e. an upper half containing the linear light source and a lower half from which light exits the wall washer luminaire 300). An edge of the upper half containing the linear light source lands on the first plane.

[0050] A greatest distance from the first plane X-Z to an edge of the reflector arrangement 320 (i.e. a peak of the bottom edge of the reflector arrangement, adjacent to a light output window of the wall washer luminaire) may be less than the greatest distance from the first plane to the curved reflective surface defined by the axis Yi. In other words, from top to bottom, the curved reflective surface curves away from the first plane and reaches a peak, before curving back towards the first plane. For instance, for a reflector arrangement having a height (in direction Z) of about 100 mm, the greatest distance from the first plane to the curved reflective surface defined by the axis Yi may be about 35-45 mm (e.g. about 40 mm), while the greatest distance from the first plane to an edge of the reflector arrangement may be about 20-30 mm (e.g. about 25 mm).

[0051] This shape of reflective surface results in light emitted towards the top of the reflector arrangement being reflected towards the bottom of a surface to be illuminated, while light emitted towards the bottom of the reflector arrangement is reflected towards the top of the surface to be illuminated, providing uniform illumination across the surface. Further, this shape reduces glare, as the curved reflective surface wraps around the linear light source.

[0052] In Figure 3, the reflector arrangement 320 comprises a plurality of reflective elements; that is, the curved reflective surface of the reflector arrangement is a faceted surface. In Figure 3, the reflective elements have a quadrilateral shape; however, other shapes that can be tessellated are also envisaged (e.g. the reflective elements may be hexagonal). The reflector arrangement may comprise reflective elements having a variety of sizes.

[0053] Each reflective element may be curved; in some examples, each reflective element may have a different curvature to the overall curvature of the curved reflective surface (e.g. each reflective element may be a portion of a sphere). For instance, each reflective element may have a radius of curvature of less than 50 mm. This has been found to provide smoother light around comers in walls. The reflective elements may be concave or convex. Preferably, each reflective element in the reflector arrangement has a same curvature. Alternatively, the reflector arrangement 320 may consist of a continuous (smooth) reflective surface.

[0054] In some examples, the wall washer luminaire 300 may further comprise a barrier 360, configured such that only light reflected by the reflector arrangement 320 is output by the wall washer luminaire. In other words, the barrier is configured to block light emitted by the linear light source 350 from directly exiting the wall washer luminaire, in order to reduce glare. The barrier 360 extends in direction X on a side of the linear light source adjacent to a light output window of the luminaire. The width and angle of the barrier may be configured such that an edge of the barrier furthest from the linear light source lies on or extends beyond a line between the top of the linear light source (i.e. a side of the linear light source furthest from the light output window) and the bottom edge of the reflector arrangement (i.e. an edge adjacent to the light output window). In some examples, a surface of the barrier 360 on which light emitted by the linear light source 350 is incident may be a reflective surface, so that light emitted by the linear light source that is incident on this surface may be reflected towards the reflector arrangement 320 and thus output by the wall washer luminaire. For instance, the surface of the barrier on which light emitted by the linear light source is incident may have a reflectivity of at least 85%.

[0055] In order to improve the uniformity of light distribution and light output ratio provided by the wall washer luminaire 300, the barrier 360 may be slanted with respect to a normal of the first plane X-Z, in a direction away from the linear light source. For instance, an angle of the barrier with respect to the normal of the first plane X-Z (in a direction away from the linear light source) may be in the range of 10-30° (i.e. an angle between the linear light source and the barrier may be in the range of 100-120°); angles in this range have been found to provide good uniformity and a high light output ratio. In particular, the angle may be in the range of 15-20°, which has been found to provide a particularly high uniformity and light output ratio.

[0056] The inventors have found that lower angles for the barrier 360 (and barriers slanted towards the linear light source, rather than away from the linear light source 350) result in a lower uniformity and light output ratio, as more of the light emitted by the linear light source is reflected by the barrier back towards the linear light source. At higher angles, the size of the barrier must increase in order to reach the line between the top of the linear light source and the bottom edge of the reflector arrangement. This results in a greater proportion of light being blocked by the barrier from reaching the light output window, thus reducing the light output ratio. Angles in the range 10-30°, and more particularly in the range 15-20°, provide a trade-off between the barrier reflecting too much light and the barrier blocking too much light.

[0057] Figure 4 illustrates a perspective view of the reflector arrangement 320 of the wall washer luminaire 300. Figure 4 illustrates the overall shape of the curved reflective surface more clearly. In order to more clearly illustrate the shape of the curved reflective surface, the linear light source and barrier have been omitted from Figure 4.

[0058] Figure 5 illustrates a sectional view of the wall washer luminaire 300, taken along lines A-A and B-B of Figure 4. The linear light source 350 is mounted on a plate 370, from which the barrier 360 extends, and the reflector arrangement is provided over the linear light source.

[0059] The axis Yi defining the greatest distance H from the first plane X-Z passes through the intersection of lines A-A and B-B; in other words, Figure 5 illustrates a cross- section of the (upper) half of the reflector arrangement 320 (divided by the third plane X-Yi) containing the linear light source 350, showing that the edge of the upper half of the reflector arrangement lands on the first plane in which the linear light source lies, making contact with the plate 370 on which the linear light source is mounted. In this way, light emitted by the linear light source is unable to leak past the edge of the upper half of the reflector arrangement, and is instead only able to exit the wall washer luminaire 300 through the light output window provided by the shape of the lower half of the reflector arrangement.

[0060] Figure 6 illustrates an exploded view of the wall washer luminaire 300. Figure 6 illustrates how the plate 370, linear light source 350 and reflector arrangement 320 fit together to form the wall washer luminaire 300.

[0061] As the skilled person will readily appreciate, the wall washer luminaire may further comprise one or more other elements, such as a heatsink (e.g. provided on an opposite side of the plate 370 to the linear light source 350), driving circuitry (e.g. an AC-DC driver), control circuitry, communication circuitry, and so on. In some examples, the wall washer luminaire 300 may further comprise the housing 110 and mounting element 140 illustrated in Figure 1, in order to allow the wall washer luminaire to be mounted on a track. In other examples, the wall washer luminaire 300 may further comprise the housing 210 illustrated in Figure 2, in order to allow the wall washer luminaire to be recess-mounted.

[0062] The wall washer luminaires disclosed herein may be mounted at a distance of 0.8-1 m of the surface to be illuminated by the wall washer luminaire (e.g. a distance of 0.9 m), and at a height (i.e. from a floor adjacent to the surface to be illuminated / the ground) of 2.5- 3.5 m (e.g. a height of 3 m). If more than one wall washer luminaire is required to illuminate a surface, the wall washer luminaires may be mounted at intervals of 1.5-2.0 m (e.g. at intervals of 1.8 m).

[0063] Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality.

[0064] 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.

[0065] If the term "adapted to" is used in the claims or description, it is noted the term "adapted to" is intended to be equivalent to the term "configured to". If the term "arrangement" is used in the claims or description, it is noted the term "arrangement" is intended to be equivalent to the term "system", and vice versa. Any reference signs in the claims should not be construed as limiting the scope.

Claims

CLAIMS:

1. A wall washer luminaire (100, 200, 300), comprising: a linear light source (350) extending in a first direction (X) and lying in a first plane (X-Z); a reflector arrangement (120, 220, 320) forming a curved reflective surface configured to reflect light emitted by the linear light source, wherein the first plane intersects the curved reflective surface such that the light source is contained within a volume delimited by the curved reflective surface, and the curved reflective surface has an overall concave shape that is curved in any plane that intersects the curved reflective surface; and a barrier (360) configured such that only light reflected by the reflector arrangement (120, 220, 320) is output by the wall washer luminaire.

2. The wall washer luminaire (100, 200, 300) of claim 1, wherein the curved reflective surface is symmetric with respect to a second plane (Y-Z), perpendicular to the first direction.

3. The wall washer luminaire (100, 200, 300) of claim 1 or 2, wherein an axis (Yi) defining a greatest distance from the first plane to the curved reflective surface in a second direction (Y) perpendicular to the first plane has a non-zero offset from the linear light source; a third plane (X-Yl), containing the axis (Yi) and parallel to the first direction (X), virtually divides the reflector arrangement into two halves, wherein an edge of the half containing the linear light source lands on the first plane.

4. The wall washer luminaire (100, 200, 300) of any of claims 1 to 3, wherein the reflector arrangement (120, 220, 320) comprises a plurality of reflective elements (325).

5. The wall washer luminaire (100, 200, 300) of claim 4, wherein each reflective element has a radius of curvature of less than 50 mm.

6. The wall washer luminaire (100, 200, 300) of any of claims 1 to 3, wherein the reflector arrangement (120, 220, 320) consists of a continuous curved reflective surface.

7. The wall washer luminaire (100, 200, 300) of claim 1, wherein an angle of the barrier with respect to a normal of the first plane (X-Z) is in the range of 10-30°.

8. The wall washer luminaire (100, 200, 300) of claim 7, wherein the angle of the barrier with respect to the normal of the first plane (X-Z) is in the range of 15-20°.

9. The wall washer luminaire (100, 200, 300) of claim 7 or 8, wherein a surface of the barrier (360) on which light emitted by the linear light source (350) is incident is a reflective surface.

10. The wall washer luminaire (100) of any of claims 1 to 9, further comprising a mounting element (140) for mounting the wall washer luminaire to a track (10).

11. The wall washer luminaire (200) of any of claims 1 to 9, further comprising a housing (210) configured for recess mounting.

12. The wall washer luminaire (100, 200, 300) of any of claims 1 to 11, wherein a greatest distance from the first plane (X-Z) to an edge of the reflector arrangement (120, 220, 320) in a second direction (Y) perpendicular to the first plane is less than a greatest distance from the first plane (X-Z) to the reflector arrangement in the second direction (Y).

13. The wall washer luminaire (100, 200, 300) of any of claims 1 to 12, wherein the curved reflective surface has a reflectivity of at least 85%.

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