| 摘要 |
PURPOSE:To provide reflection preventing films to a prism without degrading the performance of the prism by adhering the other surfaces of transparent plates having reflection preventing films on one side to the prism. CONSTITUTION:A prism which is a base body is constituted by providing a polarization separating membrane 3 via a transparent adhesive 4 between the 1st prism 1 and the 2nd prism 2. Transparent glass plates 6a, 6b, 6c which are beforehand adhered with reflection preventing films 5 on one side are adhered on the incident and exit surfaces of the prism, i.e. surfaces EF, BC, DF by directing the film 5 surfaces outward and by using the adhesive 4 having refractive indices approximate to the refractive index of the prism. Unlike the prior art wherein the reflection preventing films are provided directly to the prism by high temp. treatment such as high temp. varpo deposition, this invention is free from the degradation in the performance of the prism, such as the deformation of the adhesive 4 between the prisms 1 and 2 by the effect of high temp., etc. |
