| 摘要 |
PURPOSE:To reduce return light from a recording medium to a light source side at the time of reproducing and to lower the occurrence of noise by making a light beam incident obliquely to the face normal of the recording medium at the time of reproducing, and scanning in the direction in which projected component on the face of the recording medium becomes reverse to that of the time of recording. CONSTITUTION:Light beam 20 incident on an objective lens 14 from a light source side passes a position parallel to and off from the optic axis of the objective lens 14, and a recorded pit 21 on the recording medium is deeper in depth, steeper in gradient and larger in width at the end of writing than at the beginning of writing. When reproducing information, light beam 22 for reproduction is projected on the recording face of a light card 1 obliquely to a position parallel to and off from the optic axis through the lens 14. Projection component to the recording face at this time is made nearly reverse to the direction of scanning of a light beam spot to the recording face at the time of recording. Thereby, scattered light (shown by dotted lines) of light beam incident on an information pit 21 does not go back to the direction of incidence, and return light is not generated. |
