Patent ID: 6947367
Filing Date: 2005-09-20
Classification: G11B

Abstract:
1. An optical head comprising: laser light sources emitting a plurality of laser beams with different wavelengths; a single means for converting beam width of said plurality of laser beams, said beam width converting means having dispersion characteristics so that said plurality of laser beams emitted from said laser light sources exit at different angles when said plurality of laser beams enter at identical angles; and a single means for optically focusing said plurality of laser beams exiting from said beam width converting means to an optical spot on an optical information medium; wherein said plurality of laser beams emitted from said laser light sources include laser beams which pass through said width converting means and, at least one of said laser beams is offset in angle of entry into said focusing means relative to an exit angle of a second laser beam, and said offset is less than 1.17 degrees.