| 摘要 |
PURPOSE:To maintain the initial position relation of both beams by specifying equally the number of reflecting surfaces to reflect a laser beam from a laser source for writing and the number of the reflecting surfaces to reflect the laser beam from the laser source for monitor for a composite optical element. CONSTITUTION:At the time of an angle dislocation, a laser beam 33 is reflected on a reflecting surface 32, becomes a laser beam 33-2 of an angle 2d for a Z axis, a laser beam 34 is reflected by a polarization beam splitter 31, becomes a laser beam 34-2 of an angle 2d for the Z axis in the same way, becomes a synthesizing laser beam 36 and is emitted. Here, respective laser beams 33 and 34 are reflected once which is the same number together. Since the reflecting surface 32 and the polarization beam splitter 31 maintain a parallel relation, the dimension between the laser beam 33-2 and the laser beam 34-2 is maintained to (e) at the time of assembling in the synthesizing laser beam 36 and the relative position to the laser beam 34-2 and the laser beam 33-2 is not changed. Thus, even when reflecting surfaces 31 and 32 of a composite optical element 30 to execute the synchronization generate spatially the misregistration by the thermal expansion, etc., the initial position relation of both beams 33 and 34 can be maintained. |
