High mast Led flood light fixture generally consists of a housing and electrical (driver) compartment typically made from low copper die cast aluminum. The heavy duty aluminum flood housing is designed to accommodate all electrical and optical components. A metal core printed circuit board (MCPCB) provides the thermal connection between heat sink and LED package, electrical insulation and the transfer of electricity into the LEDs. A lens frame fixes a clear or prismatic lens made of tempered glass or impact resistant polycarbonate. The frame is then mechanically sealed with a silicone gasket for weather tight operation. One challenge in designing high power LED lighting fixtures is that the high power LEDs emit a high amount of heat. Hence, it may be advantageous to remove the heat generated by the LED from the LED semiconductor junction and maintain the internal temperature of the luminaire assembly below the maximum operating temperature so the electrical and electronic components therein maintain peak performance. Thermal management, therefore, has become increasingly important in high power LED lighting. LED floodlights feature cast aluminum heat sink behind the LED assembly to control heat buildup and dissipate heat. Heat sinks are thermal conduction pathways that is integrated into a lighting system to remove or redistribute thermal energy from LEDs through thermal conduction with these heat sources. The aerodynamic vents created by the heat sink fins generate efficient air flow and accelerate natural convection. Hot air converges smoothly into a fast laminar flow, quickly transferring heat to the ambient environment. Other thermal management strategies have utilized heat pipes that combines the principles of both thermal conductivity and phase transition heat transfer mechanism. The complete separation of the electrical compartment from the LED assembly keeps the driver and other control circuitry very cool, effectively maintaining the driver's service life in high ambient operating temperatures. The housing is pre-treated and powder-coated to resists extreme weather conditions without cracking or peeling and provide optimal color and gloss retention. The floodlight design is increasingly incorporating more aesthetic elements. The attractively styled contemporary design with smooth curves and contoured edges blend unobtrusively with the environment.
Beam Patterns
High mast led flood light design challenges every floodlight fixture designer to satisfy the demands of the client and meet the parameters of different optical solutions. The primary optic is included in the LED package, and the secondary optics are part of the floodlight fixture and are designed to shape the radiation pattern, or beam pattern, maximize efficiency and application spacing. Secondary optics provide unique optical combination possibilities to modify the LED output beam such that the output beam of the floodlights efficiently meets the desired photometric specification. LED secondary optics include reflectors, lenses, total internal reflection (TIR) lenses, and diffusers. Lens has the excellent light-gathering ability to control the distribution of light rays at a small angle. While the reflector has the advantage to redirecting the flux (illuminance) and converging the rays at a large angle. A TIR lens is a combination of lens and reflector, using the principle of total reflection optics to collect and process light. For high voltage applications it is recommended to use PMMA (acrylic) or PC (polycarbonate) lens for their high mechanical strength, excellent optical properties, good thermal stability, high thermal conductivity, and low moisture and water absorbing capacity. In high power floodlighting, lenses and TIR lenses are often used for better uniformity and higher optical efficiency (at least 90% for most applications). It makes sense, however, to use a reflector design in some applications, e.g. sports lighting, to achieve a designed beam pattern and minimize spill light and glare.
