The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 04, 2010
Filed:
Apr. 19, 2007
Mitsuo Osawa, Koriyama, JP;
Yoshiharu Ooi, Chiyoda-ku, JP;
Mitsuo Osawa, Koriyama, JP;
Yoshiharu Ooi, Chiyoda-ku, JP;
Asahi Glass Company, Limited, Tokyo, JP;
Abstract
A liquid crystal diffraction lens element and an optical head device, which can switch focal lengths of both of outgoing light and returning light by a single element, are provided. The liquid crystal lens element comprises transparent substrates, a liquid crystalsandwiched between the transparent substrates, transparent electrodes, birefringent Fresnel lens memberseach having a Fresnel lens shape and made of a birefringent material, and a seal, wherein the extraordinary refractive index direction A of the birefringent Fresnel lens memberand the extraordinary refractive index direction B of the birefringent Fresnel lens memberare perpendicular to each other, and the alignment direction of the liquid crystalat the interface between the liquid crystaland the transparent substrateis perpendicular to the alignment direction of the liquid crystalat the interface between the liquid crystaland the transparent substrate