An apparatus for detecting a pretilt angle is comprised of a light source
1, a polarizer 2, a liquid-crystal cell 3, a quarter-wave plate 4, an
analyzer 5, a photodetector 6, and a processing device. The processing
device receives from the photodetector transmitted light intensities of
light that is transmitted through the liquid-crystal cell 3 at a plurality
of light incident angles. The processing device calculates Stokes
parameters corresponding to the plurality of light incident angles based
upon the transmitted light intensity corresponding to the plurality of
light incident angles. Furthermore, an apparent retardation corresponding
to the plurality of light incident angles is determined based upon the
Stokes parameters corresponding to the plurality of light incident angles.
The pretilt angle of the liquid-crystal cell 3 is determined based upon
the determined apparent retardation corresponding to the plurality of
light incident angles.
