Circularly-polarized-light-extracting optical element having chlosteric layer with changing chiral pitch

摘要

Disclosed herein is a process of producing a circularly-polarized-light-extracting optical element adapted to effectively prevent the appearance of bright and dark stripes on the screen of a display to avoid lowering of the displaying quality of the display. The circularly-polarized-light-extracting optical element includes a glass substrate 11 , an alignment layer 12 laminated to the glass substrate 11 , and a cholesteric layer 13 formed on the alignment layer 12 , in which molecules are aligned in the sate of planar alignment due to the alignment-regulating action of the surface of the alignment layer 12 . The cholesteric layer 13 has a first surface 13 a on its glass substrate 11 side, and a second surface 13 b opposite to the first surface 13 a. Director directions of molecules on the first surface 13 a of the cholesteric layer 13 are aligned in substantially one direction owing to the alignment-regulating action of the surface of the alignment layer 12 . Further, the chiral pitch in the cholesteric layer 13 varies so that the chiral pitch p₂ on the second surface 13 b side is longer than the chiral pitch p₁ on the first surface 13 a side.