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TECHNOLOGY CORNER: Cold Cathode Fluorescent Lighting
Nov 13 2009
Cold cathode fluorescent lighting (CCFL) is not a new technology—it’s been around for at least 70 years and is currently used in a number of applications such as backlighting for computer displays, decorative lighting and sign illumination. The new CCFLs are more efficient than incandescents and last far longer than either compact fluorescent lamps (CFLs) or incandescents.
CCFLs are similar to conventional fluorescent lighting except the lamps use a different type of cathode. Conventional fluorescent lamps use a thin filament that is heated by current passing through it. Electrons boil off when the filament gets hot enough. Cold cathode lamps use thick electrodes and high voltages to knock electrons off without any extra heating, which is where the “cold cathode” name comes from.
Because they use thick electrodes, the CCFLs have a long lamp life—at least 25,000 hrs. They also feature simpler electronics, which makes them easier to miniaturize. Their small size, long life, and low bulb wall temperatures make them ideal for backlighting liquid crystal display (LCD) computer displays, where the light source is in close proximity to components that could be damaged by heat. CCFLs are still the leading backlight source for LCDs, but LEDs are starting to make inroads.
Also, unlike CFL lifetimes, the life of a CCFL is independent of the number of starts, enabling the products to be used in signs requiring rapid flashing and in applications using occupancy sensors. Other target markets include accent lighting and use in decorative lighting fixtures such as chandeliers, where their dimming capability is a big plus.
More recently, some low-wattage products have been released that compete with incandescents and CFLs. The products come in a variety of colors and shapes including A-line and decorative. In low wattages the CCFLs provide better efficacy than incandescents and equal or better efficacy than CFLs. They also offer longer life, and are dimmable on conventional incandescent dimmers, unlike low-wattage CFLs.
Many public utility lighting efficiency programs offer incentives for qualifying installations of CCFLs. Contact your local utility for details.
Information provided courtesy of Bonneville Power Administration.
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