Materials to improve performances of discharge lamps

Lighting is responsible for the consumption of more than 2650 TWh of energy per year, corresponding to about 20% of the global electricity consumption. All the strategies and international policies pushing for the adoption of more efficient light sources are assuming a real important role for energy saving and for reduction of greenhouse gas emissions. Since there is a 75-85% difference between the energy consumption of the least efficient and the most efficient lighting technologies available on the market, it is expected that upgrading the lamps to higher levels could significantly reduce the household's total electricity consumption. Nowadays compact fluorescent lamps are gradually replacing incandescent lamps in residential lighting; in offices, commercial and industrial buildings, where lighting electricity consumption is quite relevant, linear, compact, circular fluorescent lamps and HID lamps are widely adopted. Light-emitting diodes (LEDs) are a fast emerging technology, however their use for general lighting is still quite limited because it is difficult to find LEDs fulfilling the expectations of the consumers in terms of light output and price. Solid state light sources are likely going to become valid alternatives to discharge lamps in many fields, but some years are still needed. In the meantime it is important to favor the use of discharge lamps that have high efficiency and improved performances thanks to the adoption of suitable materials and components. This paper will illustrate technological approaches that can contribute at improving the performances of low pressure mercury lamps and HID (High Intensity Discharge) lamps. Advancements and optimization of materials, such as getters, active amalgams, starting amalgams, can allow to produce light sources with superior characteristics. Concerning the aspect related to innovative materials it is worth underlining that many of the fluorescent lamps today available on the market are using advanced technological solutions based on stable mercury compounds for accurate and reliable Hg dosing, down to very low levels.