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Twin Hg-free HPS lamp Disclosure Number: IPCOM000171752D
Publication Date: 2008-Jun-18
Document File: 1 page(s) / 44K

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Twin Hg-free HPS lamp


Today's state of the art HPS lamps contain a relatively high amount of Hg, which is environmentally hazardous compound. Hg-free lamps do exist, but only for 100W lamp power and more. At this moment Hg- free lamps do not have a large market share of the total HPS market, but this may grow in the future if the performance of the Hg-free lamps improves and/or legislation is going to reduce or ban the use of Hg.

Problems or disadvantages overcome

The reason that Hg-free lamps are only available at 100W or more is the design of the arc tube. HPS lamps require a 100V lamp voltage to allow operation on standard gear. To reach this voltage the Hg-free lamps must either have an arc tube with a very low internal diameter or the tube must be very long. Following these design rules the arc tube would become unacceptably thin or long for lamp powers below 100W.

The essential features of the improvement

To avoid the use of an extremely long and thin arc tube two arc tubes are assembled in series. Together the arc tubes give enough lamp voltage for use on regular lamp gear. The 2 tubes can be placed next to each other so that the total size of the lamp does not increase compared to a normal (Hg-containing) lamp. This would make the low power Hg-free lamp retrofit with the current lamp portfolio.

Detailed description of an embo...