In the top tiers of many professional sports, it is a requirement for stadiums to have floodlights to allow games to be scheduled outside daylight hours. Evening or night matches may suit spectators who have work or other commitment earlier in the day. The main motivation for this is television marketing, especially in sports such as Gridiron which rely on TV rights money to finance the sport. Some sports grounds which do not have permanent floodlights installed may make use of portable temporary ones instead. Many larger floodlights (see bottom picture) will have gantries for bulb changing and maintenance. These will usually be able to accommodate one or two engineers.

Types of floodlight

The most common type of floodlight is the Metal Halide which emits a bright white light, however most commonly used for sporting events are high pressure Sodium floodlights which emit a soft orange light, similar to that of street lights; SON lamps have a very high lumens per watt ratio making them a cost effective choice where certain lux levels have to met.

By the nature of the device, an emergency light is designed to come on when the power goes out. Every model, therefore, requires some sort of a battery or generator system that could provide electricity to the lights during a blackout. The earliest models were incandescent light bulbs which could dimly light an area during a blackout and perhaps provide enough light to solve the power problem or evacuate the building. It was quickly realized, however, that a more focused, brighter, and longer-lasting light was needed. The modern emergency floodlight provides a high-lumen, wide-coverage light that can illuminate an area quite well. Some lights are halogen, and provide a light source and intensity similar to that of an automobile headlight.

Early battery backup systems were huge, dwarfing the size of the lights for which they provided power. The systems normally used lead acid batteries to store a full 120-volt charge. For comparison, an automobile uses a single lead acid battery as part of the ignition system. Simple transistor or relay technology was used to switch on the lights and battery supply in the event of a power failure. The size of these units, as well as the weight and cost, made them relatively rare installations. As technology developed further, the voltage requirements for lights dropped, and subsequently the size of the batteries was reduced as well. Modern lights are only as large as the bulbs themselves – the battery fits quite well in the base of the fixture.

The term “solid state” refers commonly to light emitted by solid-state electroluminescence, as opposed to e.g. incandescent bulbs (which use thermal radiation) or fluorescent tubes. Compared to incandescent lighting, SSL creates visible light with reduced heat generation or parasitic energy dissipation. Even conventional fluorescent lamps are essentially solid state light sources, as most light is generated in the solid state fluorescent coating of the tube. Conventional incandescent light bulbs are essentially solid state light sources too, as light is generated in the solid state tungsten filament. The distinction is even more blurry in the case of most common “white” LEDs which convert blue light to an (approximate) white light spectrum using photoluminescence, the same principle used in conventional fluorescent tubes.

The typically small mass of a solid-state electronic lighting device provides for greater resistance to shock and vibration compared to brittle glass tubes/bulbs and long, thin filament wires. They also eliminate filament evaporation, potentially increasing the lifespan of the illumination device.

Solid-state lighting is often used in traffic lights and is also used frequently in modern vehicle lights, train marker lights, remote controls etc.