| 摘要 |
<P>PROBLEM TO BE SOLVED: To achieve stabilized light-emitting operation by dealing with change in the luminous efficiency due to temperature change within the lighting period, and variation in the emission luminance incident thereto, without applying a large load to a control system. <P>SOLUTION: The light source device comprises: a light source unit 24 using semiconductor light-emitting elements; a light source driver 44 which makes the light source unit 24 emit light by supplying a drive signal thereto; an illuminance sensor 28 which detects the emission state of the light source unit 24 at the start and end of the emission period; a control unit 41 which generates a current adjustment signal and a delay characteristics switching signal (output through a D/A converter 42) depending on the detection result of the illuminance sensor 28; and an inverting circuit 45 and a delay circuit 43 for supplying to the light source driver 44 the current adjustment signal, having delay characteristics being set variably by the switching signal from the control unit 41, while delaying the current adjustment signal. <P>COPYRIGHT: (C)2013,JPO&INPIT |
