It is to provide a large-diameter imaging lens that can suppress reduction of peripheral light amount, achieve size and weight reduction, and maintain excellent optical performance. A silicon resin is applied to fill a gap between the connector body and the circuit board. At least two of the amplified spontaneous emission light generating sections are connected together in series. In one embodiment, the flexible portion is itself of a thickness of at least about 3 mm, and the cut-out portion forms an opening in the flexible portion. The reference voltage generation circuit generates a first reference voltage when an output voltage of the switching power supply is a first output voltage and a second reference voltage lower than the first reference voltage when the output voltage is a second output voltage.