Back to results
US 5,471,456 AGranted
Optical medium recording apparatus with a rotatable optical beam deflector
AssigneesAsahi Kogaku Kogyo Kabushiki Kaisha, Nippon Hoso Kyokai
InventorsHaruki Tokumaru, Koichi Maruyama, Syunitirou Wakamiya
Life of this patent
Estimating the term…
Abstract
An optical recording and reproducing apparatus is provided with a light source that emits a beam of light, a rotatable head including a deflector that deflects the beam in a predetermined direction and an objective lens group which forms an image of the beam on an optical recording medium. The rotatable head rotates about an optical axis of the beam which is incident upon the rotatable head. A movable lens group, provided in an optical path of the beam between the light source and the rotatable head, is movable in at least an optical axis direction.
Claims30
An optical recording and reproducing apparatus comprising:
- a light source that emits a beam of light;
- a rotatable head including a deflector which deflects said beam in a predetermined direction and an objective lens group which focuses an image of said beam on an optical recording medium, wherein said rotatable head rotates about an optical axis of said beam which is incident upon said rotatable head;
- a movable lens group provided along the optical axis of said beam between said light source and said rotatable head, wherein said movable lens group is driven in at least the optical axis direction;
- and
- a relay lens group provided between said movable lens group and said objective lens group, wherein an exit pupil of said movable lens group is made substantially conjugate with an entrance pupil of said objective lens group by said relay lens group.
2 more elements
An optical recording and reproducing apparatus comprising:
- a light source;
- an objective lens group which focuses a plurality of beams on an optical recording medium;
- a focusing lens group provided along an optical axis of said beams between said light source and said objective lens group, wherein said focusing lens group is driven along the optical axis direction, wherein a point located at a predetermined distance from a rear principal point of said focusing lens group is maintained substantially conjugate with a front focal point of said objective lens group, and wherein said predetermined distance is equivalent to a distance between said light source and a front principal point of said focusing lens group, said rear principal point being defined as the principal point of said focusing lens group on an objective lens side of said optical axis, said front principal point being defined as the principal point of said focusing lens group on a light source side of the optical axis, and said front focal point being defined as the focal point of said objective lens group on said light source side of the optical axis.
An optical recording and reproducing apparatus comprising:
- a light source that emits a beam of light;
- a rotatable head including a deflector which deflects said beam in a predetermined direction and an objective lens group which focuses an image of said beam on an optical recording medium, wherein said rotatable head rotates about an optical axis of said beam which is incident upon said rotatable head;
- a movable lens group provided along the optical axis of said beam between said light source and said rotatable head, wherein said movable lens group is driven in at least a plane perpendicular to said optical axis;
- and
- a relay lens group provided between said movable lens group and said objective lens group, wherein an exit pupil of said movable lens group is made substantially conjugate with an entrance pupil of said objective lens group by said relay lens group.
2 more elements
An optical recording and reproducing apparatus comprising:
- a light source;
- an objective lens group which focuses a plurality of beams on an optical recording medium;
- a focusing lens group provided along an optical axis of said beams between said light source and said objective lens group, wherein said focusing lens group is driven along the optical axis direction;
- and
- a relay lens group provided between said focusing lens group and said objective lens group, wherein a point located at a predetermined distance from a rear principal point of said focusing lens group is maintained substantially conjugate with a front focal point of said objective lens group by said relay lens group, and wherein said predetermine distance is equivalent to a distance between said light source and a front principal point of said focusing lens group, said rear principal point being defined as the principal point of said focusing lens group on an objective lens side of said optical axis, said front principal point being defined as the principal point of said focusing lens group on a light source side of the optical axis, and said front focal point being defined as the focal point of said objective lens group on said light source side of the optical axis.
2 more elements
Dependencies are inferred from the claim text.