Asahi Glass Company, Limited

Mitsuo Oosawa

Yoshiharu Ooi

Takuji Nomura

Yuzuru Tanabe

Hiromasa Sato

Toshimasa Kakiuchi

Kouichi Murata

Ryuichiro Shimizu

A liquid crystal lens element capable of finely adjusting focal length according to the magnitude of applied voltage, and an optical head device employing such a liquid crystal lens element, are provided. On one surface of a transparent substrate, a transparent electrodeand a concave-convex portionmade of a transparent material having a cross section shape approximated by a saw-tooth shape, are formed so as to constitute a plurality of annular portions, and on one surface of a transparent substrate, a transparent electrodeis formed. The transparent electrodesandconstitute annular divided electrode segments, and division positions of the annular electrode segments are made to be agree with division positions of annular portions of the saw-tooth-shaped concave-convex portionof the transparent substrate

Liquid crystal lens element and optical head device

A liquid crystal lens element is provided, which does not produce change of transmission wavefront regardless of polarization state of incident light when it is off-state at a time of no voltage application, and which exhibits concave lens function for extraordinarily polarized incident light when it is on-state at a time of voltage application. In a liquid crystal lens elementcomprising a pair of transparent substratesandand a liquid crystal layersandwiched between the transparent substrates, which is configured to change convergent point of light transmitted through the element according to the magnitude of voltage applied to the liquid crystal layerthe liquid crystal lens elementfurther comprises a Fresnel lenshaving a concave-convex-shaped cross section formed on the transparent substrate, a first transparent electrodeformed on a flat surface of the transparent substrateon which the Fresnel lensis formed, and a second transparent electrodeformed on a flat surface of the other transparent substrate

Liquid crystal lens element optical head device

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 crystalaccording to the magnitude of the voltage applied to the liquid crystalsandwiched between a pair of transparent substratesand, which comprises transparent electrodesandprovided on the respective transparent substratesandfor applying a voltage for the liquid crystal, and a concave-convex portionhaving a saw-tooth-shaped cross-sectional shape having a rotational symmetry about an optical axis and formed on one surface of the transparent electrodewith a transparent material, wherein at least concave portions of the concave-convex portionare filled with the liquid crystalso as to change the substantial refractive index of the liquid crystalaccording to the magnitude of applied voltage.

Growing community of inventors

Koriyama, Japan

Mitsuo Oosawa