Next Steps in Environmentally Friendly Xenon HID 2007-01-1232
In 2004 environmental-friendly mercury free xenon HID lamps - D3 and D4 respectively with and without integrated igniter - were introduced in the automotive headlighting market. Driven by an increased concern for the environment from all stake holders in the car industry mercury free xenon HID has started his successful replacement of mercury containing xenon HID lamps used for automotive head lighting all over the world.
Of course, the elimination of mercury was a key factor in promoting the environmental friendliness of xenon HID. Furthermore the amount of radioactive thorium compounds could be reduced to 2% of the content of the D1/D2 bulbs.
Since then mercury free bulb designs without any thorium content have been studied assessing the electrical and optical compatibility with existing mercury free system designs.
It is shown that the complete elimination of thorium is possible if the thermal management of the bulb is controlled properly without sacrificing lumen or beam maintenance.