Folded optical system with improved image insulation

摘要

An optical collimating assembly for imaging light from a display. The optical assembly includes first and second linear polarization filters having polarization directions that are orthogonal to one another. A folded imaging assembly that includes a first beam splitter, a first ¼ wave plate, and a second beam splitter is located between the polarization filters. A second ¼ wave plate is also located between the polarization filters. The first ¼ wave plate has a birefringence axis that is orthogonal to the birefringence axis of the second ¼ wave plate. In the preferred embodiment of the present invention, the ¼ wave plates are constructed from the same birefringent material. One of the reflectors is preferably constructed from a material having a reflectivity that depends on the direction of linear polarization of light striking the beam splitter.