| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a beam splitting element where, in a beam splitter composed in such a manner that two prisms are mutually joined via an optical thin film, acoustic noise caused by reflected light at the inside face is reduced. <P>SOLUTION: The beam splitting element is provided with: a cube beam splitter composed in such a manner that two orthogonal prisms are mutually joined via an optical thin film; a transparent flat plate installed with a tilt to one side face of either prism composing the cube beam splitter and composed of a transparent material having a refractive index equal to that of the prism; a tilt angle controlling means holding the transparent flat plate and also making the tilt angle variable; and a transparent liquid packed at a gap between the side face of either prism and the transparent flat plate and having a refractive index equal to that of the prism and the transparent flat plate. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
