| 摘要 |
PROBLEM TO BE SOLVED: To provide a device in which the positive pulse width of an external control signal (5) is made fixed to prevent the lack of a control signal caused by the delay of the signal form of an external control signal, and a discharge lamp is prevented from turn off light. SOLUTION: In an ac power supply (1) and a light control type discharge light lighting device (2), the light control type discharge light lighting device (2) has the ac power supply (1) as a power source. The external control signal (5) is inputted from a light control terminal (4) and received through a photo coupler (6) to turns on light of the discharge lamp (3). The external control signal (5) varies a positive DUTY ratio by varying a positive pulse DUTY ratio by fixing a positive pulse width and varying the period of a pulse signal. The optical out put of the discharge lamp (3) is varied by the external control signal (5). COPYRIGHT: (C)2005,JPO&NCIPI |
