PROTECTIVE FILM FOR HIGH-LUMINOUS INTENSITY METAL HALIDE DISCHARGE LAMP

摘要

PURPOSE: To extend the service life of a high luminous intensity metal halide electric discharge lamp, by preventing metal composition of metal halide sealing material in the lamp from being lost substantially and the free halogen from accumulating subsequently. CONSTITUTION: A protective coat 12 with proper composition and thickness is placed on the inner surface of an arc tube 14 for a lamp 10. An adequate lamp 10 has an arc tube 14 which is made of fused silica and covered by a silicon protective coat 12. It is preferable that chemical vapor deposition process is used to cover the arc tube 14 with a silicon protective coat 12.