It is an object of the present invention to provide a nitrogen-containing condensed ring compound, which can be used as an organic n-type semiconductor having an excellent electron transport property and which is also excellent in terms of solubility in an organic solvent. The light module is mounted in the housing, and includes a light source, a light guide, and a light tight shield. The ground station then determines the position of the satellite, the beam and beam color, and further computes the frequency, polarization, and time slot, among other information, to communicate with the satellite. A liquid crystal polarity inversion signal generator receives one of the sub frame flag signal, the N-line flag signal, and the frame flag signal in response to a selection signal, and generates a liquid crystal polarity inversion signal.