Wide view supertwisted nematic liquid-crystal light shutter.
We present a novel concept of a wide viewing angle liquid-crystal display (LCD) light shutter, taking advantage of the highly symmetric 180 degrees -twisted liquid-crystal (LC) configuration and the light propagation starting with a single mode. In a specific case of the high voltage driven LCD light shutter, the resulting very high overall symmetry allows for the efficient angular compensation of the light attenuation in the optically closed state using just a simple, specifically tuned, negative-birefringent c-plate retarder. The latter can be adapted to compensate for the positive optical birefringence of the homeotropically aligned LC molecules as well as also for a great deal of the angular dependence of the crossed polarizers. We show that the additional partial compensation of the angular dependence of the crossed polarizers can be explained by a combined effect of the positive birefringence of the homeotropically aligned LC molecules, negative-birefringence c-plate retarder, and an in-plane residual positive birefringence (a-plate) of the boundary layers of the LC molecules.
Vrecko
Andrej
A
Institute Jozef Stefan, Slovenia.
Pirs
Janez
J
Bazec
Matej
M
Ponikvar
Dusan
D