abstract |
[PROBLEMS] To provide a discharge lamp 1 which suppresses a decrease in light transmittance and has a long lamp life. A rare gas and mercury are sealed in an arc tube. On the inner wall surface of the arc tube 2, an oxide ceramic film 5 is formed. The oxidized ceramic film 5 prevents the influence of hydrogen ions on the arc tube 2, suppresses a decrease in light transmittance of the arc tube 2, and prolongs the lamp life. |