Optical information detection apparatus
AssigneeFujitsu Limited
InventorsNobuhide Aoyama, Shinya Hasegawa
Life of this patent
Estimating the term…
Abstract
An optical information detecting apparatus includes a first optical system focusing an optical beam on a recording surface of a recording medium and a second optical system directing a reflection optical beam produced as a result of reflection of the optical beam by a recording surface of the recording medium to a photodetection unit. The second optical system includes a beam dividing element disposed so as to intercept the reflection optical beam and divide the reflection beam into a plurality of optical beam elements traveling generally parallel with each other in the reflection optical beam, such that the plurality of optical beam elements reach the photodetection unit along respective optical paths.
Claims18
An optical information detecting apparatus optically detecting information recorded on a recording medium, said optical information detecting apparatus being adapted to hold said recording medium and comprising:
- a beam source;
- a first optical system focusing an optical beam produced by said beam source on a recording surface of said recording medium;
- a photodetection unit;
- and
- a second optical system directing an optical beam, produced as a result of irradiation of said optical beam on said recording surface, to said photodetection unit,
- said second optical system including a beam dividing element disposed so as to incident said produced optical beam, said beam dividing element extracting, from said produced optical beam, a plurality of optical beam elements traveling generally parallel with each other in said reflection optical beam, by dividing said produced optical beam such that said plurality of optical beam elements reach said photodetection unit along respective optical paths,
- wherein said photodetection unit includes first and second photodetectors on respective optical paths of first and second optical beam elements included in said produced optical beam for detecting an information signal recorded on a land formed on said recording surface of said recording medium and wherein said photodetection unit includes third and fourth photodetectors on respective optical paths of third and fourth optical beam elements includes in said produced optical beam for detecting an information signal recorded on a groove formed on said recording surface of said recording medium.
An optical information detecting apparatus optically detecting information recorded on a recording medium, said optical information detecting apparatus being adapted to hold said recording medium and comprising:
- a beam source;
- a first optical system focusing an optical beam produced by said beam source on a recording surface of said recording medium;
- a photodetection unit;
- and
- a second optical system directing an optical beam, produced as a result of irradiation of said optical beam on said recording surface, to said photodetection unit,
- said second optical system including a beam dividing element disposed so as to incident said produced optical beam, said beam dividing element extracting, from said produced optical beam, a plurality of optical beam elements traveling generally parallel with each other in said reflection optical beam, by dividing said produced optical beam such that said plurality of optical beam elements reach said photodetection unit along respective optical paths,
- wherein said beam dividing element applies a first optical phase compensation to a first optical beam element included in said plurality of optical beam elements and a second optical phase compensation to a second different optical beam element included in said plurality of optical beam elements.
Dependencies are inferred from the claim text.