| 摘要 |
PURPOSE:To project two linear polarized beams onto the 1st and the 2nd switching optical paths and prevent crosstalk due to light scattering by using a couple of beam splitters for polarization and separation and an electrooptic element as an optical path switching element. CONSTITUTION:An incident light beam 1 from an optical path A of incidence is incident on the 1st polarization beam splitter 4 and separated into two linear polarized beams 1a and 1b in a straight traveling and a perpendicular direction. The beam 1a is passed through an element 11 in an off state without changing its direction of polarization, projected from the 2nd polarization beam splitter 5 at right angles, and changed in the direction of polarization by an element 12 in an on state to obtain the beam 1a, which becomes the beam 1a again through a half-wavelength plate 13 and passes through a polarizing element 16, and is projected from the beam splitter 4 at right angles to be projected on the 1st switching optical path A1. Scattered light generated while the element 12 is on is blocked by the polarizing element 16. Then, the beam 1b reaches the optical path A1 through elements 9, 5, 7, 6, 14, and 4. |
