Glass composition suitable for use in a fluorescent lamp, tube and lamp envelope manufactured from said glass composition, and fluorescent lamp having a lamp envelope manufactured from said glass composition.

摘要

A new type of glass, for example for use as a TL-envelope glass which as regards phosphor poisoning and Hg penetration has better properties than the present TL-envelope glasses. Phosphor poisoning occurs in particular upon fusing electrodes and bending and severing and bridging, respectively, during the manufacture of SL and PL lamps.

The composition of the glass is derived from the glass which is described in published German Patent Application 3 046 594.

Phosphor poisoning is controlled by incorporating little or no Na<Sub>2</Sub>0 in the glass. In order to nevertheless reach good processing properties, a combination of Li<Sub>2</Sub>0 and K<Sub>2</Sub>O is used in the glass. The addition of only Li<Sub>2</Sub>O or only K<Sub>2</Sub>0 does not result in a suitable glass.

Hg penetration is controlled by the presence of a large quantity of alkaline earth metal oxides in the glass.

The glass according to the invention has a good light transmission. A lamp comprising a lamp envelope of a glass according to the invention shows only a small luminous decline during operation of the lamp.