A driver circuit and a diagnostic method are provided. A semiconductor layer is commonly used by the switching and driving transistors. To this end, a tube made of a material that fuses with the insulation sheath and the cable channel when heated is slipped over the cable section of the connection cable lying inside the cable channel. It comprises focus mechanism for adjusting the image forming position of lens system by moving the third lens group13 in the same direction as optical axis. The soft-start circuit is arranged to provide the soft-start reference voltage from a reference voltage. The method includes providing a silicon substrate having a plurality of carbon nanotubes disposed on a silicon layer and coupling the silicon substrate to a top surface of a packaging substrate, wherein the plurality of carbon nanotubes are coupled to a plurality of substrate pads of the packaging substrate.