| 摘要 |
PURPOSE:To obtain the split optical head where dust, etc., does not enter by making internal optical components abut on the opening parts of a fixed head part and a movable carriage part and sealing the opening parts. CONSTITUTION:The opening part 14a' of the fixed head part 14' has necessary irreducible area and a polarization beam splitter 5 is mounted on a pedestal 20 and abuts on a circumferential frame part 21 to close the opening part 14a' from inside. The opening part 13a' of the movable carriage part 13' also has necessary irreducible area and a mirror 6 is placed on a pedestal 22 and made to abut on the the circumferential frame part 23 of the opening part 14a' from inside, thereby sealing the opening part. This constitution prevents dust, etc., from entering the fixed head part and movable carriage part. In this case, even if dust sticks on the surface of the splitter 5 or mirror 6, it can be wiped away with cloth, etc., to clean the surface. |
