The invention relates to a plastic film, at least one side of which is provided with a surface structure comprising parallel rows of elevations. In this manner, water is at least partially removed from the aqueous fiber stock to form a highly consistent paper fiber stock. Further, a cover 6 made of resin which is opened on the beam-output side of the semiconductor laser chip 4 is fixed to the heat radiation block 2 so as to surround the semiconductor laser chip 4 and the portions of the leads 3A, 3B protruding on the reference-surface side in conjunction with the heat radiation block 2. The system, method and terminals may operate using TCPIP protocol.