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U.S. Philips Corporation

Adrianus J H P Van Der Pol

Leonie Maria Geerdinck

Johannes H Roes

Emmanuel W J L Oomen

The discharge vessel encloses a discharge space provided with a filling of mercury and a rare gas in a gastight manner. Each end portion ( ) of the lamp supports an electrode ( ) arranged in the discharge space. An electrode shield ( ) encompasses at least one of the electrodes ( ) and has a substantially spiral-shaped cross-section. Preferably, the electrode shield ( ) is made from a ceramic material and is covered with a material which reacts with or forms an alloy with alkaline earth metals released by the electrode ( ).

Low-pressure mercury vapor discharge lamp with a spiral-shaped electrode shield

Low-pressure mercury vapour discharge lamp is provided with a discharge vessel (,) and a first and a second end portion (,). The discharge vessel (,) encloses a discharge space (,) provided with a filling of mercury and a rare gas in a gastight manner. Each end portion (,) supports an electrode (,) which is arranged in the discharge space (,). Current supply conductors (,) through the end portions (,) to outside the discharge vessel (,). A UV-reflecting shield (,) is positioned in the space between the electrodes (,) and the end portions (,) from the creation of reactive sites in the end portions (,) at which reactive sites mercury is bound. Preferably, the shield (,) is attached to the current supply conductors (,&prime;). The lamp according to the invention has a comparatively low mercury consumption.

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Eindhoven, Netherlands

Adrianus J H P Van Der Pol