REFLECTOR

Abstract: A reflector for a luminaire comprises a light source (6), a column (8) and a housing (2), and has a light-source facing surface for reflecting light. The reflector (4) comprises a first, upper tier (12) having a light scattering surface arranged so as, in use, to direct the light from the light source generally vertically downwards towards the base of the column and a second, lower tier (14) having a high precision light reflecting surface arranged so as, in use, to direct the light towards the ground and away from the base of the column. The reflector is preferably generally square in plan.

Description: Title: Reflector The present invention relates to an improved reflector for a luminaire. The reflector is particularly suitable for use with a luminaire which forms part of an exterior lighting system, in which the luminaire is one of an array of luminaires arranged to light an area such as a car park or a town centre. Luminaires are known which can be arranged in an array to provide a lighting system to light an area such as a car park or a town centre. It is increasingly a problem with such systems that they are required to satisfy stringent planning regulations regarding both aesthetic considerations and light pollution, and also they are required to satisfy increasingly stringent technical specifications with regard to average and minimum lighting levels. The problem of light pollution can be considered as three separate issues identified as skyglow, overspill and glare. By "skyglow" is meant the light from the luminaire that illuminates the sky. By "overspill" is meant the light which spreads into areas adjacent to the area which is being lit and by "glare" is meant the discomfort or impairment of vision experienced when part of the visual field is excessively bright in relation to the general surroundings. Known luminaires comprise a housing, a reflector and a light source and are manufactured in a number of different shapes and sizes. As noted above, planning regulations control not only the light pollution available, but also the external appearance of the luminaire. In general, the less obtrusive the luminaire, the more likely the planning authorities are to approve it. Known luminaires have the disadvantage that they cause unacceptably high levels of one or more of the above defined forms of light pollution, they may only be able to meet technical specifications for minimum illumination by having an inefficiently high average level of illumination and/or they may be aesthetically unacceptable. In a known design of reflector, the top surface of the reflector has been provided with a diffuse surface finish in order to provide lower intensity illumination around the base of the column with improved uniformity. In the case of a vertically burning light source, this diffuse reflector covers the entire top surface and requires a high sided main reflector, which in turn requires a deep outer luminaire edge, which may give rise to planning objections. The present invention provides a reflector for a luminaire comprising a light source, a column and a housing, which reflector has a light source facing surface for reflecting light, characterised in that the reflector comprises a first, upper tier having a light scattering surface arranged so as, in use, to direct the light from the light source generally vertically downwards towards the base of the column and a second, lower tier having a high precision light reflecting surface arranged so as, in use, to direct the light towards the ground and away from the base of the column. The reflector may be of any suitable shape, but in a preferred embodiment of the reflector according to the invention, it is generally square in plan. The generally square plan shape of the reflector may be modified to improve the light output pattern, in particular by providing side reflector inserts and by clipping the corners of both the upper and lower tiers in order to reduce trapping of light in the corners. The housing of the luminaire, in which the reflector is to be installed may be of any suitable shape to receive the reflector, for example it may be square or circular in plan. The light source facing surface of the upper tier of the reflector, which is designed to scatter the light and to direct a diffuse beam of light downwards towards the base of the column on which the luminaire is mounted, preferably has a dimpled surface. The light source facing surface of the lower tier of the reflector, which is designed to direct the light towards the ground, away from the base of the column, is preferably a highly polished high precision surface. The reflector is preferably made from aluminium, but may alternatively be made of any other suitable material, such as aluminised plastic. An embodiment of a reflector for a luminaire will now be described with reference to the accompanying drawings, in which Figure 1 is a side view, in section, of an embodiment of a reflector installed within a luminaire; Figure 2 is a plan view of the reflector of Figure 1 and Figure 3 is a similar view to that of Figure 1, with a simplified schematic view of the light output. As can be seen from Figure 1, a luminaire shown generally at 10 comprises a housing 2, reflector 4, light source 6 and column 8. The reflector 4 is substantially square in plan, and comprises a first, upper tier 12 and a second, lower tier 14. The inner surface of the upper tier 12 is provided with a dimpled surface finish to scatter light. The inner surface of the lower tier 14 is provided with a highly polished, high precision reflecting surface finish. As can be seen from Figure 2, the reflector 4 is generally square in plan. The corners 16, 16', 16" and 16'" of the upper tier 12 are clipped to reduce losses due to trapping of light. In a similar manner, the corners 18, 18', 18" and 18'" of the lower tier 14 are also clippedand additionally provided with reflector inserts to improve the light distribution. Side reflector inserts 20, 20', 20" and 20'" are located along the side walls of the lower tier 14 to improve further the light distribution. As can be seen from Figure 3, light originating from the light source 6 strikes the top and side inner surfaces of the upper tier 12 and is directed downwards towards the base of the column 8. Light originating from the light source 6 also strikes the inner side surfaces of the lower tier 14 and is directed in a controlled manner towards the ground, away from the base of the column 8. Since the lamp arc of the light source 6 is in the same plane as the lower tier 14 of the reflector, there is no direct upward light.

Claims: Claims 1. A reflector for a luminaire comprising a light source, a column and a housing, which reflector has a light-source facing surface for reflecting light, characterised in that the reflector comprises a first, upper tier having a light scattering surface arranged so as, in use, to direct the light from the light source generally vertically downwards towards the base of the column and a second, lower tier having a high precision light reflecting surface arranged so as, in use, to direct the light towards the ground and away from the base of the column. 2. A reflector as claimed in claim 1, characterised in that it is generally square in plan. 3. N reflector as claimed in claim 2, characterised in that it comprises side reflector inserts located in the side walls of the lower tier 4. A reflector as claimed in claim 2 or claim 3, characterised in that the corners of both the upper and lower tiers are clipped. 5. A reflector as claimed in any of claims 1 to 4 characterised in that the light source facing surface of the upper tier of the reflector has a dimpled surface. 6. A reflector as claimed in any of claims 1 to 5 characterised in that the light source facing surface of the lower tier of the reflector has a highly polished high precision surface. 7. A reflector as claimed in any of claims 1 to 6 characterised in that the reflector is made from aluminium. 8. A reflector for a luminaire substantially as herein described and with reference to the accompanying drawings. 9. N luminaire comprising a reflector, a light source, a column and a housing characterised in that it comprises a reflector as claimed in any of claims 1 to 8. 10. N luminaire as claimed in claim 9 characterised in that the housing is circular in plan.

Inventors: AUSTIN KELVIN JOHN, AUSTIN, KELVIN, JOHN
Applicants: ABACUS HOLDINGS LTD, AUSTIN KELVIN JOHN, ABACUS HOLDINGS LIMITED, AUSTIN, KELVIN, JOHN
Application year: 1999
Main classification: F21S8
IPC codes: F21S8, F21V7