CLEAR TO CIRCULAR POLARIZING PHOTOCHROMIC DEVICES AND METHODS OF MAKING THE SAME

摘要

The present invention provides optical elements comprising a photochromic linear polarizing element and a birefringent layer that circularly or elliptically polarizes transmitted radiation. The photochromic linear polarizing element comprises a substrate and either: (1) a coating comprising an aligned, thermally reversible photochromic-dichroic compound having an average absorption ratio of at least 1.5 in an activated state, and being operable for switching from a first absorption state to a second absorption state in response to actinic radiation, to revert back to the first absorption state in response to thermal energy, and to linearly polarize transmitted radiation in at least one of the two states; or (2) an at least partially ordered polymeric sheet connected to the substrate; and a thermally reversible photochromic-dichroic compound that is at least partially aligned with the polymeric sheet and has an average absorption ratio greater than 2.3 in the activated state.