| 摘要 |
PURPOSE:To enable the formation of a wide guide groove with good recording and reproducing characteristics by making a deviation period of a write beam spot <= 1/2 of a diameter of the write beam spot and forming the guide groove having a constant width which is the same as or more than the diameter of the write beam spot. CONSTITUTION:A wobble signal fv for oscillating an n-th diffracted light beam Ln outputted by a light beam deflecting system 2 at a prescribed amplitude is outputted by a 2nd signal generating circuit 10, while a carrier wave signal fc outputted by a 1st signal generating circuit 9 is FM-modulated by an FM modulating circuit 11 with the wobble signal fv. Consequently, a spot Ls of a primary diffracted light beam L1 is oscillated with a deviation period T of <=1/2 of the spot diameter d21 on a recording surface (photoresistance film C) of a recording disk R in relation to a driving mechanism 8 based on the wobble signal fv, so that the groove G of a constant width which is the same as or more than the diameter of the write beam spot Ls can be formed. By this method, the wide groove G of good recording and reproducing characteristics is formed with a single spot Ls without mistracking. |
