Patent ID: 6304542
Filing Date: 2001-10-16
Classification: G11B

Abstract:
Dual wavelength optical pickup head for use in an optical disk writing and/or reading device comprising:optical means for directing light beams of a first and a second wavelength emitted by a first and a second light source to an optical disk, the optical means comprising at least a wavelength selective beam splitter which allows to at least partially change the direction of a light beam of the first wavelength and is transmissive for a light beam of the second wavelength;focusing means for focusing the light beams on a layer of the optical disk;photodetection means for detecting with a single detector light of each one of the first or the second wavelength reflected by the layer of the optical disk;further optical means for directing a reflected light beam reflected by the layer to the photodetection means; and whereinsaid focusing means comprises a dual focus lens objective.