| 摘要 |
PURPOSE:To prevent deviation in optical paths by constituting a matrix driving mechanism in such a way that when a total reflection mirror forming double sided mirrors retreats from a grating point the nonreflection film adjacent to this is disposed on the grating point. CONSTITUTION:A total reflection film 2 and a nonreflection film 3 are coated respectively by half surface each on the surface on one side of a thin transparent substrate 1 (glass plate), and a nonreflection film 3 is coated over the entire surface on the reflection side. A matrix driving mechanism is so constituted that when the film 2 retreats from a grating point the film 3 adjacent to this is disposed on the grating point. When such double sided mirror is used, the light in an optical path A in an X direction is totally reflected and advances on an optical path B in a Y direction. However, when the switch is changed over, the light of the path A refracts and the light of an optical path C is totally reflected by the double sided mirrors and coincides with the transmitted light from the path A, whereby the deviation of the optical paths is prevented. |
