Posted by Donald Rowe on 28th Jul 2020
Asymmetric and Full Cutoff LED Flood Lights are important for applications where there is a need to reduce obtrusive lighting or light pollution in the form of light spill and light glare into the area surrounding the playing area. Asymmetric and full cut-off flood lights do this by eliminating upward light projection. So there is no light emitted above horizontal. This can also improve safety and spectator comfort.
Traditionally, metal halide sports flood lights have achieved a full cut off flood light by using internal reflectors and large shields or so called "shielding reflectors" originally developed for street lighting. You may have noticed older tennis court lights designed to be full cut off are mounted on relatively high 12 metre poles and tilted slightly upward at < 10°. This alone leads to the projection of upward light but you will notice that the tennis court lights also have a relatively large visor or glare shield which extends down to horizontal. This enables these older tennis court lights to be full cut-off. Although their light spill is still much greater than modern full cut off LED sports lights.
Modern LED Sports Flood Lights use a polycarbonate lens system to focus and aim the light much like a camera lens whether than be for close or distant applications. Using a lens system a lone is much more superior to the older reflector and glare shield systems, in that the lens directs the light precisely to the target area on the sports oval or tennis or netball court, much like a spot light, such that there is considerably less light spill and the use of glare shields is not really necessary, depending on the vertical angle of the lights. Different spherical beam angles or lenses such as narrow 15°or 30° can focus the light on more distant areas whilst maintaining intensity and reducing light spill. These are typically used for larger sporting applications like cricket, soccer and hockey fields, football ovals, and other large sporting centres. Wider spherical beam angles such as 45° to 100° are typically used for lighting closer applications or filling in areas close to the poles. By using more specialised beam combinations and computer simulations the light can be focused perfectly onto the playing area whilst enabling a reduction in power consumption of the lights and lower electricity costs. Depending on the vertical angle of the light these spherical beam flood lights they will still produce a relatively high level of glare and a minimal level of light spill, which brings us to the use of asymmetric beam LED flood lights.
As mentioned, the way to eliminate glare and light spill is to use full cutoff lighting. LED sports flood lights achieve this by using an asymmetric lens system. This produces a non-spherical or rectangular light pattern such as 100°x 60° thereby creating a relatively wide horizontal beam but a reduced vertical beam, thereby reducing upward light spill. However, this alone is not considered a full cutoff.
Full Cutoff LED sports flood lights are achieved by using a more specialised asymmetric lens system such as 130°x 25° which not only provides a high projection rectangular beam pattern but also projects the light outward and forward across the tennis or netball court or sporting oval. The full cut off is achieved by being able to mount the Asymmetric LED Sports Light at a perfectly horizontal or 0° position. By design this creates a full cutoff light which has little or no upward light scatter, aside from that reflected by the court or sporting oval. In this application, typically used for tennis or netball courts, there is no vertical tilt on the lights such that they all point downwards in a perfectly flat position. However, in turn, the asymmetric lens system allows for the superior projection of the light across and onto the court with very uniform and even coverage.
You can read more about our asymmetric led sports flood lights in the following link:
http://www.liteonled.com.au/tennis-court-netball-court-lighting/