An apparatus and method for force mounting semiconductor packages onto printed circuit boards without the use of solder. The driver unit has a characteristic that an absolute value of a current flowing through the second terminal increases with a potential of the first terminal to the second terminal, and controls light emission of the light emitting unit based on a potential difference between the first terminal and the second terminal. An attached battery pack functions as a stabilizing ballast. Further, it is possible to effectively reduce the cost for the die required for the forging work.