| 摘要 |
PROBLEM TO BE SOLVED: To achieve life prolongation by suppressing deterioration of an electrolytic capacitor.SOLUTION: In a control part 5, except that when all light sources parts 1 and 2 are turned off, the duty ratio of a switching power supply circuit of respective lighting circuit parts 3 and 4 is increased and decreased in a range of 100% from a predetermined lower limit value (for example 1%) which is higher than 0%. Accordingly, even when the a light control ratio is set the lowest, a minute current can be made to continuously flow through smooth capacitors C1 of the lighting circuit parts 3 and 4, thereby preventing the smooth capacitors C1 from being left to stand under high temperature environment in a non-contact state. As a result, deterioration of the smooth capacitors C1 (electrolytic capacitors) is suppressed and life prolongation of a lighting device can be achieved. |
