| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a polarization conversion element which can redesign a design retardation, surely increasing a polarization conversion efficiency in a predetermined wavelength band to be equal to or more than a prescribed value. <P>SOLUTION: A polarization conversion element includes: a polarization separation element 21 including a translucent substrate 21A which is made of an inorganic crystal material having a birefringence and an optical rotation, and through which an entering S polarization exits from an emission side surface thereof while keeping a polarization plane, and a polarization separation section 21B which is provided on an incident side surface of the translucent substrate 21A, which separates entering light into P polarization P and S polarization S, and which is transmissive for the P polarization P and is reflective for the S polarization S; a reflective element 22 which is arranged approximately parallel to the translucent substrate 21A with an air gap interposed therebetween and which reflects the S polarization S reflected by the polarization separation section 21B, in a direction approximately parallel to a light path of the P polarization P passing through the polarization separation section 21B; and a 1/2 wave plate 23 which is arranged between the reflective element 22 and the translucent substrate 21A and which emits, as the P polarization P, the polarization plane of the S polarization S reflected by the polarization separation section 21B. <P>COPYRIGHT: (C)2013,JPO&INPIT |
