Patent ID: 6160783
Filing Date: 2000-12-12
Classification: G11B

Abstract:
An optical pick-up device recording on and/or playing back a first optical disk having a transparent substrate of a first thickness and a second optical disk having a transparent substrate of a second thickness, said second thickness being greater than said first thickness, comprising:a laser (10) producing a laser beam (18) having a predetermined polarization direction (17);a rotation element (11) for rotating a polarization direction (17) of said laser beam (18) by approximately 90.degree. in recording on or playback of said first or second optical disk;an objective lens (15) for focusing said laser beam (18) on a signal recording surface (80, 90) of said first or second optical disk; anda polarizer (14) blocking a perimeter of said laser beam (18) in recording on or playback of said second optical disk; whereinsaid rotation element (11) includesa first transparent electrode (22) located at an incident side of said laser beam (18),a second transparent electrode (23) located at an emissive side of said laser beam (18), and opposite to said first transparent electrode (22),a first rubbing film (24) formed on an inner surface of said first transparent electrode (22) and having a first rubbing direction (28) substantially parallel or perpendicular to a polarization direction of said laser beam (18),a second rubbing film (25) formed on an inner surface of said second transparent electrode (23) and having a second rubbing direction (29) substantially perpendicular to said first rubbing direction (28), andliquid crystal (26) interposed between said first rubbing film (24) and said second rubbing film (25).