| 摘要 |
PROBLEM TO BE SOLVED: To accurately determine coming of a replacement time by considering not only a cumulative time of use of a light source but also other conditions influencing the life of the light source. SOLUTION: A device includes: a first calculation means 11 for calculating a cumulative time of use (ΣT) of the light source 4; a keeping means 10 for keeping the cumulative time of use calculated by the first calculation means; a second calculation means 11 for calculating a lighting stress time equivalent (Ta) obtained by converting stress applied to the light source every time the light source is lit once to a time of use of the light source; an update means 11 for updating the cumulative time of use kept in the keeping means by adding the lighting stress time equivalent calculated by the second calculation means to the cumulative time of use and by using the summed value thereof; and a determination means 11 for determining coming of a replacement time of the light source when the cumulative time of use exceeds a predetermined reference value by comparing the cumulative time of use kept in the keeping means with the predetermined reference value. COPYRIGHT: (C)2007,JPO&INPIT |
