| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a lighting device that can highly accurately control each optical output from a plurality of types of LED chips having different luminescent colors, while reducing its cost. <P>SOLUTION: A lighting device comprises: a photodiode 4 for detecting light emitted from a plurality of types of LED chips 1a, 1b and 1c having different luminescent colors; a current-voltage conversion circuit 6 for conducting current-voltage conversion of an output current from the photodiode 4, the circuit having a conversion coefficient determination section 61 connected between an inverted input terminal and an output terminal of an arithmetic amplifier OP1, for determining a conversion coefficient for the current-voltage conversion, the conversion coefficient determination section 61 capable of selecting the conversion coefficient for each of the LED chips 1a, 1b and 1c having different luminescent colors so as to have reduced difference in dynamic range of an output voltage from the current-voltage conversion circuit 6 among the LED chips 1a, 1b and 1c having different luminescent colors; and a control section 10 having a function for controlling the conversion coefficient determination section 61 so that the conversion coefficient is determined according to each luminescent color during a period in which each LED chip having each luminescent color is lighted independently for each luminescent color. <P>COPYRIGHT: (C)2012,JPO&INPIT |
