HIKARIKIROKUBAITAINOMAESHORISOCHI

摘要

PURPOSE:To change at a high speed the entire surface of an optical disk into a state of a high optical constant by using an optical system which leads the light radiated from a light source onto an optical recording medium in a fixed form and then shifting the irradiating position of the light on the recording medium. CONSTITUTION:The light is dispersed in both the tangent and radius directions of a disk by means of cylindrical lenses 7 and 8. The dispersed light having a diameter larger than the aperture diameter of an objective lens 9 is obtained in the radius direction of the disk, and the peripheral light is cut off by the aperture of the lens 9. While the dispersed light of the tangent direction of the disk has a diameter smaller than the aperture diameter of the lens 9. For the distance between the lens 9 and the disk 5, the focus servo is applied by a control means 10 so that the recordingsurface of the disk is set at the focal position of parallel beams. It is possible to vary the sizes and distribution of the spots on the disk by changing both the focal distance and the focal position of the lenses 7 and 8.