Open AccessLiquid-crystal variable-focus lenses with a spatially-distributed tilt angles
Author(s) -
Mareki Honma,
Toshiaki Nose,
Satoshi Yanase,
Rumiko Yamaguchi,
Susumu Sato
Publication year - 2009
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.17.010998
Subject(s) - rubbing , optics , liquid crystal , materials science , tilt (camera) , polyimide , homeotropic alignment , liquid crystal display , focus (optics) , lens (geology) , stylus , focal length , layer (electronics) , physics , geometry , composite material , acoustics , mathematics
A pretilt angle controlling method by the density of rubbings using a tiny stylus is proposed. The control of the surface pretilt angle is achieved by rubbing a side-chain type polyimide film for a homeotropic alignment. Smooth liquid crystal (LC) director distribution in the bulk layer is successfully obtained even though the rough surface orientation. This approach is applied to LC cylindrical and rectangular lenses with a variable-focusing function. The distribution profile of the rubbing pitch (the reciprocal of the rubbing density) for small aberration is determined to be quadratic. The variable focusing function is successfully achieved in the LC rectangular lens, and the voltage dependence of the focal length is tried to be explained by the LC molecular reorientation behavior.