Patent ID: 7085218
Filing Date: 2006-08-01
Classification: G11B

Abstract:
1. An optical head device comprising: a light source; an objective lens for focusing onto an optical recording medium the light which is emitted from said light source and travels on a going path; a photodetector for detecting the light which is reflected from said optical recording medium and travels on a returning path; and a liquid crystal panel, for producing wave aberration by which the wave aberration of the light traveling on the going path is canceled, comprising a first substrate, a first liquid crystal portion, a second substrate, a second liquid crystal portion and a third substrate which are laminated in this order, wherein said liquid crystal panel further produces wave aberration by which the wave aberration of the jight traveling on the returning path is canceled, and wherein a first pattern electrode is formed on any one of the surface of said first substrate which confronts said first liquid crystal portion and the surface of said second substrate which confronts said first liquid crystal portion while a second pattern electrode is formed on the other surface, and a third pattern electrode is formed on any one the surface of said second substrate which confronts said second liquid crystal portion and the surface of said third substrate which confronts said second liquid crystal portion while a fourth pattern electrode is formed on the other surface.