MAGNETO-OPTICAL DISK DEVICE

PURPOSE:To make the detection interval of recording marks constant and to reduce data errors at the time of reproduction by providing an optical element enlarging the elliptical factor of the spot of the emitted light of a semiconductor laser element generating the light of a light source. CONSTITUTION:A laser beam being an S-polarization emitted from the semiconductor laser element 11 is converted to parallel laser beams by a collimating lens 12 and converted to be a state in which the elliptical factor of a beam form is enlarged through a beam shaping element 13 being the optical element. After then, beams are reflected on the splitting plane 14a of a polarizing beam splitter 14 to emit from the cabinet 15 of a fixed optical system 5 and converged on a magnetic disk 1 through a polarizing prism 16, an objective lens 17 and further, reflected again. The form of the edge part of recording marks being formed on recording tracks is made to be nearly a line-shape, the interval of recording marks is made constant and the probability of generating data errors at the time of reproduction is reduced by enlarging the elliptical factor of the spot of the laser beams being converged on the tracks on the magneto- optical disk 1 in such a manner.