A liquid crystal lens element having a lens function is provided, which is
small sized without having moving part, and which can stably carry out
correction of spherical aberration containing a power component
corresponding to focal point change of incident light.A liquid crystal
lens element which changes a focal length of light transmitted through a
liquid crystal 16 according to the magnitude of the voltage applied to
the liquid crystal 16 sandwiched between a pair of transparent substrates
11 and 12, which comprises transparent electrodes 13 and 14 provided on
the respective transparent substrates 11 and 12 for applying a voltage
for the liquid crystal 16, and a concave-convex portion 17 having a
saw-tooth-shaped cross-sectional shape having a rotational symmetry about
an optical axis and formed on one surface of the transparent electrode 13
with a transparent material, wherein at least concave portions of the
concave-convex portion 17 are filled with the liquid crystal 16 so as to
change the substantial refractive index of the liquid crystal 16
according to the magnitude of applied voltage.