Abstract
Patterns of wall blackening on ceramic metal halide discharge lamps are investigated to quantitatively evaluate relative contributions of degradation mechanism.
Sample prepared with 2 minutes turn on/ 3minutes turn off operation procedure had shown a homogeneous blackening, while the tube of a continuously operate lamp exhibited blackening thicker toward the direction of gravity.
Contribution to the wall blackening due to wall reaction during continuous operation seems to predominate electrode sputtering at the discharge commencement judging from the light transmittance distribution of tested lamps.
