| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce flicker of a discharge lamp even when performing data communication and to dim the discharge lamp at a dimming level based on user's desire. <P>SOLUTION: In a luminaire 2, a dimming signal input part 23 of a control circuit part 21 inputs a dimming signal and calculates on-duty. A converting part 25 uses a data table of a data storing part 24 to set operation frequencies of a "high level" and a "low level" from the on-duty. When data are input from a signal source 20 in this state, a converting part 25 converts the data into a conversion pattern of four-valued PPM and controls an operation frequency of an inverter circuit part 28 through an oscillation circuit part 27 of a lighting circuit 22. The inverter circuit part 28 supplies high frequency current to the discharge lamp 1 in accordance with the operation frequency of the "high level" or "low level" and lights the discharge lamp 1. A receiver 3 receives light 10 of the discharge lamp, and demodulates data on the basis of a variation of a frequency of the received light 10. <P>COPYRIGHT: (C)2008,JPO&INPIT |
