AU2011101060A4 - A Luminaire - Google Patents

Abstract

A luminaire, including: a frame, a reflective surface for reflecting light from a light source, and a diffuser element coupled to the frame; wherein the diffuser element is movable between at least a first position such that the luminaire produces a first beam, and a second position such that the luminaire produces a second beam which is more diffuse than the first beam. FIG 1a

Description

Regulation 3.2 AUSTRALIA Patents Act 1990 INNOVATION PATENT SPECIFICATION (ORIGINAL) Name of Applicant: Brightgreen Pty Ltd PO Box 1021, St Kilda South Post Office St Kilda South VIC 3182 Australia Address for Service: DAVIES COLLISON CAVE, Patent Attorneys, I Nicholson Street, Melbourne 3000, Victoria, Australia Innovation Patent specification for the invention entitled; "A Luminaire" The following statement is a full description of this invention, including the best method of performing it known to us: A LUMINAIRE Field of the invention 5 The present invention relates to luminaires. It is particularly, though not exclusively, applicable in the context of luminaires used in solid state lighting. Background 10 Luminaires (also known as light fittings or light fixtures) are used for a wide variety of indoor and outdoor lighting applications. Luminaires commonly used to illuminate indoor spaces generally include a frame for affixing the luminaire to a support such as a wall or ceiling and to house its functional components, a reflector, and a light source. The light source may take various forms including an incandescent or fluorescent lamp, for example. 15 The type of luminaire used to light an internal space is generally chosen depending on the uses to which that space is to be put. For example, in a residential setting, a study may be uniformly illuminated by a first light source at a lux level of 100, while a desk area within the study might be illuminated with a second, directional light source which provides a 20 brighter lux level of 320. In some circumstances it may be desired to change the lighting within a room. It is possible to adjust the brightness level of a luminaire using a dimmer. However, a dimmer can only adjust the brightness, and not the type of lighting. If, for example, a luminaire installed in a 25 wall or ceiling provides directional lighting, but uniform or diffuse lighting is desired, then the luminaire must be removed and replaced with an alternative luminaire which provides the desired illumination properties. It would therefore be desirable to provide a luminaire which addresses at least one of the 30 above problems, or at least provides a useful alternative.

-2 Summary of the invention In a first aspect of the present invention, there is provided a luminaire, including: a frame, a reflective surface for reflecting light from a Light source, and a diffuser 5 element coupled to the frame; wherein the diffuser element is movable between at least a first position such that the luminaire produces a first beam, and a second position such that the luminaire produces a second beam which is more diffuse than the first beam. 10 The invention therefore provides means for switching between different types of lighting, for example from directional lighting when the diffuser element is in the first position, to diffuse lighting when the diffuser element is in the second position, in a single luminaire. A person may easily switch between the first and second beams simply by moving the diffuser element to the appropriate position. 15 In one embodiment, in the second position, the diffuser element is interposed between the light source and the reflective surface. In this embodiment, therefore, light is refracted and/or scattered through the diffuser prior to reflection from the reflective surface. 20 The diffuser element may be pivotable between the first position and the second position. A pivoting movement may provide greater ease of use than alternative means of movement, for example sliding movement of the diffuser within a grooved channel. In one embodiment, the diffuser element is mounted at or near midpoints of opposed edges 25 of the frame. The frame may include retention means for releasably retaining the diffuser element in the second position. Thus, for example, the first position may be the default position for the diffuser element whilst the second position is maintained only if the retention means is 30 active.

-3 The luminaire may include further elements. For example, the luminaire may include a dimmer in order to provide control over brightness as well as lighting type. It may also include a heat sink coupled to the frame. 5 The luminaire may be a recessed luminaire suitable for installation in a wall or ceiling. Brief description of the drawings Embodiments of the invention will now be described, by way of non-limiting example 10 only, with reference to the accompanying drawings in which: Figure Ia is a perspective view of a luminaire in a first stable configuration; Figure lb is an exploded view of the luminaire of Figure la; Figure 2a is an alternative perspective view of the luminaire of Figure la; 15 Figure 2b is a front plan view of the luminaire; Figure 2c is a section through the line A-A of Figure 2b; Figure 2d is a detail of part of Figure 2c; Figure 3a is a front view of the luminaire in an intermediate configuration; Figure 3b is a section through the line A-A of Figure 3a; 20 Figure 4a is a perspective view of the luminaire in a second stable configuration; Figure 4b is a front plan view of Figure 4a; Figure 4c is a section through the line A-A of Figure 4b; and Figure 4d is a detail of part of Figure 4c. 25 Detailed description of the drawings Referring initially to Figures la and lb, there is shown a lurninaire 10 including a frame 12 and a reflective surface 14 for reflecting light from a light source 16. The light source 16 may comprise one or more LEDs, which are in thermal contact with a heat sink 18 for 30 dissipating heat generated by the LEDs during operation of the luminaire 10. For example, the LEDs may be housed within a recessed area in the heat sink 18.

-4 The luminaire assembly 10 also includes a diffuser element 20 having a diffuser plate 22 and a rod 24 for mounting the diffuser element 20 to the frame 12 via mount points 13 for pivoting movement as will later be described. Assembly 10 also includes an adapter plate 5 30 having a pair of clips 32, and retention means 34 for the diffuser element 20. The retention means 34 is a resilient plate. The adapter plate 30 is preferably moulded as a single component from a resilient material such as a plastics material. The diffuser plate 22 is a transparent or translucent plate having some surface roughness 10 (on either or both surfaces), which may be introduced by sandblasting for example. The surface roughness results in scattering of light which passes through the plate, producing a softer lighting effect than is produced by direct reflection from reflective surface 14. In other embodiments, the diffuser plate 22 may be a prismatic diffuser, or another type of refractive and/or scattering diffuser, depending on the particular diffuse lighting effect 15 which is desired. To assemble the luminaire 10, the adapter plate 30 is attached to light source 16 by pushing clips 32 into apertures 19. The heat sink 18 is then attached to frame 12 by threading screws through screw holes 40, 42 which are formed in the heat sink 18 and frame 12 20 respectively. Opposed ends of the rod 24 are then clipped into mount points 13 so that diffuser plate 22 is pivotable about an axis of the rod 24. The mount points 13 are located at midpoints of opposed edges 12a, 12b of the frame 12. The luminaire 10 shown in the Figures is particularly suitable for installation in a wall 25 cavity. When installed, the heat sink 18 and the frame 12, apart from its chamfered edge 17, are seated within the wall cavity, while chamfered edge 17 abuts against the edges of the wall cavity, so that an aesthetically pleasing front face 50 is presented. Other components such as connection to a power source, and a driver for the LEDs, may also be located in the wall cavity. This type of luminaire is generally referred to as an embedded or 30 a recessed luminaire.

Turning now to Figures 2a to 2d, the luminaire 10 is shown in a first stable configuration in which the diffuser element 20 is in a first position. In the configuration shown in Figures 2a to 2d, the plate 22 of diffuser element 20 rests against the reflective surface 14 of the luminaire 20, with the edge 23 of the plate sitting just clear of the chamfered edge 17 of the 5 frame 12 (Figure 2d), leaving a small gap to allow a person to insert a fingernail to assist in lifting the plate 22 away from the reflective surface 20. With the diffuser 20 in this position, light from LEDs of the light source 16 can strike reflective surface 14 directly and produce a first beam to illuminate a space adjacent to the wall. In this configuration, the luminaire 10 is operating in direct lighting mode. 10 The luminaire 10 can be switched to a diffuse lighting mode as follows by pivoting diffuser 20 in a generally upwards direction, as shown in the intermediate configuration of Figures 3a and 3b. Once the edge 23 of diffuser plate 22 has travelled through a sufficiently large angle, it engages with a catch 35 at the edge of the resilient plate 34, as 15 best shown in Figures 4c and 4d. Although the diffuser 20 may be pushed beyond the catch 35, it will tend to fall under gravity once the pushing force is no longer applied, until the edge 23 once again engages with catch 35. In the second stable configuration of the luminaire 10 as shown in Figures 4a to 4d, the 20 diffuser element 20 is in a second position in which it is interposed between the light source 16 and the reflective surface 14. Light from the light source will therefore either pass directly through the diffuser 20, or be reflected from reflective surface 14 and then pass through diffuser 20. The result is a second beam which is more diffuse than the first beam produced when the luminaire 10 is in direct lighting mode. In this second stable 25 configuration, the luninaire 10 is in diffuse lighting mode. In order to return the luninaire 10 to direct lighting mode, the diffuser 20 can be pushed slightly upwards, and the resilient plate 34 simultaneously pushed upwards, so that diffuser 20, once released, will fall beyond the catch 35 and again rest against the reflective surface 30 14 as shown in Figures 2a to 2d.

-6 Advantageously, the luminaire 10 described above can be easily switched between two different modes of operation to provide different types of lighting as required. Further, by mounting the diffuser 20 at a midpoint of the frame 12, the front face 50 of the luminaire 10 will appear substantially identical in the two modes of operation, as will be evident 5 from Figures 2b and 4b. Many modifications will be apparent to those skilled in the art without departing from the scope of the invention as defined in the claims appended hereto. 10 The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgement or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates. 15

Claims (5)

1. A luminaire, including: a frame, a reflective surface for reflecting light from a light source, and a diffuser 5 element coupled to the frame; wherein the diffuser element is movable between at least a first position such that the luminaire produces a first beam, and a second position such that the luminaire produces a second beam which is more diffuse than the first beam. 10

2. A luminaire according to claim 1, wherein in the second position, the diffuser element is interposed between the light source and the reflective surface.

3. A luminaire according to claim I or claim 2, wherein the diffuser element is pivotable between the first position and the second position. 15

4. A luminaire according to claim 3, wherein the diffuser element is mounted at or near midpoints of opposed edges of the frame.

5. A luminaire according to any one of the preceding claims, wherein the frame 20 includes retention means for releasably retaining the diffuser element in the second position.