Patent ID: 6081498
Filing Date: 2000-06-27
Classification: G11B

Abstract:
An optical pickup compatible with at least two types of recording media, the optical pickup comprising:a first laser light source to emit a first light beam having a relatively long wavelength;a second laser light source to emit a second light beam having a relatively short wavelength;an objective lens to focus the second light beam emitted from said second laser light source on an information recording surface of a second of at least two types of optical recording media, wherein the information recording surface of the second optical recording medium is a first distance from the objective lens, to form an optical spot optimized to the second recording medium;a collimator to collimate an incident beam of light and to transmit the collimated light beam to the objective lens;a beam splitting plate to transmit one of the first and second light beams from the corresponding one of said first and second laser light sources, and reflecting the other one of said first and second light beams from the corresponding other one of said first and second light sources, to transmit the first and second light beams to said collimator as the incident light beam; andan aberration correction plate located on an optical path between said beam splitting plate and one of said first and second light sources, to correct an optical aberration occurring due to said beam splitting plate,wherein an information recording surface of a first of the at least two types of optical recording media is a second distance from said objective lens greater than said first distance, and an optical distance from said first laser light source to the information recording surface of the first optical recording medium is shorter than an optical distance from said second laser light source to the information recording surface of the second optical recording medium, thereby removing a spherical aberration occurring when the first light beam is used.