History of hid lamp

HID lamps are typically used when high levels of light over large areas are required, and when energy efficiency and/or light intensity are desired. These areas include gymnasiums, large public areas, warehouses, movie theaters, football stadiums, outdoor activity areas, roadways, parking lots, and pathways. More recently, HID lamps have been used in small retail and even residential environments because of advances in reduced lumen bulbs. Ultra-High Performance (UHP) HID lamps are used in LCD or DLP projection TV sets or projection displays as well.

HID lamps have made indoor gardening practical, particularly for plants that require high levels of direct sunlight in their natural habitat; HID lamps, specifically metal halide and high-pressure sodium, are a common light source for indoor gardens. They are also used to reproduce tropical intensity sunlight for indoor aquaria.

Most HID lamps produce significant UV radiation, and require UV-blocking filters to prevent UV-induced degradation of lamp fixture components and fading of dyed items illuminated by the lamp. Exposure to HID lamps operating with faulty or absent UV-blocking filters causes injury to humans and animals, such as sunburn and arc eye. Many HID lamps are designed so as to quickly extinguish if their outer UV-shielding glass envelope is broken.

Beginning in the early 1990s, HID lamps have been employed in motor vehicle headlamps. This application has met with mixed responses from motorists, who appreciate the improved nighttime visibility fromHID headlamps but object to the glare they can cause. Internationalized European vehicle regulations require such headlamps to be equipped with lens cleaners and an automatic self-leveling system to keep the beams aimed correctly regardless of vehicle load and altitude, but no such devices are required on motorcycles, or in North America, where ECE regulations are inapplicable and inherently more glaring beam patterns are also permitted. The fitting ofHID conversion kits (which include HID lamps that fit into original headlamp units in place of the original bulbs with no change to the headlamp's lens, reflector or housing) generally results in extremely high levels of glare, and is illegal throughout most of the world. However, complete halogen headlamp units can be replaced with complete HID headlamp units, provided that the replacement headlamp units comply with the applicable standards.