| 摘要 |
PURPOSE:To incline the carrier of the title device so that the offset quantity can be suppressed to a very small range by setting the distance between the polarizing point of the incident optical axis of a polarizing member and an object lens about double of the focal distance of the object lens against an optical disk. CONSTITUTION:The distance (l) from the polarizing point of the incident optical axis of the beam splitter (BS) of a carrier to the center of an object lens 19 and the focal distance (f) of the lens 19 against an optical disk 1 are set to l=2f. When the carrier rotates around X axis (perpendicular to the plane of the figure) which is perpendicular to the seeking direction at an angle of theta, the offset quantity DELTAx between the incident optical axis 23 of the BS 20 and the reflecting optical axis 24 from the BS 20 goes to DELTAx 2(l-2f)theta. Since l=2f, the DELTAx goes to DELTAx=0. Therefore, even when the carrier is inclined, the offset quantity becomes zero. |
