A fluorescent lamp phosphor is a phosphor material or a mixture of different materials that can mimic a wide rage of colors, including natural sunlight. Phosphors are inorganic substances that absorb energy and re-emit it as light. They offer a broad range of light color emissions and can absorb and convert energy from many different sources including optical, electrical, even mechanical or thermal energies.
In a fluorescent lamp, phosphors are used to absorb high energy ultraviolet light and convert such energy to visible light. Fluorescent lamps use an electric current to create ultraviolet (UV) light. The electric current passes through a tube containing argon and mercury vapor. The current excites the mercury vapor, causing electrons to move to higher energy levels. The electrons then fall back to lower energy levels, releasing photons of light. The photons hit a phosphor coating on the inside of the tube, which converts the UV light into visible or non-visible (e.g., infrared) light.
Fluorescent lamps use a blend of phosphors. Here are some common phosphors used in these lamps:
- Calcium halophosphate: Produces cool white light.
- Zinc orthosilicate or Tb3+-activated CeMgAl11O19: Emits green light.
- Yttrium vanadate or Yttrium Oxide: Produces red light.
- Barium disilicate or Barium Magnesium Aluminate: Provides blue light.
By combining these phosphors, fluorescent lamps can produce a range of light colors from warm white to cool white. This mix ensures efficient and effective lighting for various applications.
Fluorescent lamps are more efficient than incandescent lamps, but less efficient than most LED lamps. They have a luminous efficacy of 50–100 lumens per watt. Fluorescent lamps contain mercury, which is a neurotoxin. If a fluorescent bulb breaks or is disposed of improperly, the mercury can contaminate water supplies.
Fluorescent lamps use phosphor mixtures to convert ultraviolet light from the gas discharge into visible (generally white) light