Apparatus for polarization conversion

摘要

An apparatus for polarization conversion having a light source for supplying vertically and horizontally linearly polarized light to an optical path and a parabolic mirror disposed in the optical path and proximate to the light source. In different embodiments, the parabolic mirror has a mirror coating to induce a phase shift of 0 DEG , 90 DEG , or an arbitrary phase shift between incident light and reflected light. A polarizer, preferably a reflective polarizer film, is disposed in the optical path for reflecting light of one of the linear polarizations and for transmitting the other linear polarization. Lastly, one or more waveplates are disposed in the optical path between the polarizer and the parabolic mirror. The waveplates have opposing segments each having axes which are antiparallel to each other for recycling the reflected linear polarization by converting it to the transmitted polarization.