Optical pick-up device and objective lens used therein
AssigneeKonica Corporation
InventorsKoji Honda, Katsuya Sakamoto, Yuichi Atarashi, Kohei Ota
Life of this patent
Estimating the term…
Abstract
An optical pickup apparatus conducts recording or reproducing information for an information recording plane of a first or second optical information recording medium and comprises a first light source and a second light source mounted on a same base board; a converging optical system; and a coupling lens. The converging optical system comprises an objective lens to converge a first or second light flux having passed through the coupling lens on a first or second optical information recording medium; and a diffractive structure to change a focal length in accordance with a wavelength of a light flux emitted from the first light source or the second light source.
Claims80
An optical pickup apparatus, comprising:
- a light source unit in which a first light source to emit a first light flux having a wavelength λ1 and a second light source to emit a second light flux having a wavelength λ2 (λ2>λ1) are mounted on a same base board;
- a converging optical system to conduct recording or reproducing information for an information recording plane of a first optical information recording medium having a first protective base plate having a thickness t1 by converging the first light flux from the first light source on the information recording plane of the first optical information recording medium and to conduct recording or reproducing information for an information recording plane of a second optical information recording medium having a second protective base plate having a thickness t2 (t2>t1) by converging the second light flux from the second light source on the information recording plane of the second optical information recording medium;
- a coupling lens into which the first light flux emitted from the first light source or the second light flux emitted from the second light source proceed to be incident;
- an objective lens to converge the first or second light flux having passed through the coupling lens on the first or second optical information recording medium;
- and
- a diffractive structure to change a focal length in accordance with a wavelength of a light flux emitted from the first light source or the second light source.
An optical pickup apparatus, comprising:
- a light source unit in which a first light source to emit a first light flux having a wavelength λ1 and a second light source to emit a second light flux having a wavelength λ2 (λ2>λ1) are mounted on a same base board;
- a converging optical system to conduct reproducing information for an information recording plane of a first optical information recording medium having a first protective base plate having a thickness t1 by converging the first light flux from the first light source on the information recording plane of the first optical information recording medium and to conduct recording or reproducing information for an information recording plane of a second optical information recording medium having a second protective base plate having a thickness t2 (t2>t1) by converging the second light flux from the second light source on the information recording plane of the second optical information recording medium;
- the converging optical system including an objective lens to converge the first light flux from the first light source or the second light flux from the second light source, wherein a divergent angle or a converging angle of the second light flux from the second light source is different from that of the first light flux from the first light source.
An objective lens for use in an optical pickup apparatus which comprises a light source unit in which a first light source to emit a first light flux having a wavelength λ1 and a second light source to emit a second light flux having a wavelength λ2 (λ2>λ1) are mounted on a same base board;
- a converging optical system to conduct recording or reproducing information for an information recording plane of a first optical information recording medium having a first protective base plate having a thickness t1 by converging the first light flux from the first light source on the information recording plane of the first optical information recording medium and to conduct recording or reproducing information for an information recording plane of a second optical information recording medium having a second protective base plate having a thickness t2 (t2>t1) by converging the second light flux from the second light source on the information recording plane of the second optical information recording medium;
- a coupling lens into which the first light flux emitted from the first light source or the second light flux emitted from the second light source proceed to be incident;
- comprising:
- the objective lens to converge the first or second light flux having passed through the coupling lens on the first or second optical information recording medium;
- and
- a diffractive structure to change a focal length in accordance with a wavelength of a light flux emitted from the first light source or the second light source.
An objective lens for use in an optical pickup apparatus which comprises a light source unit in which a first light source to emit a first light flux having a wavelength λ1 and a second light source to emit a second light flux having a wavelength λ2 (λ2>λ1) are mounted on a same base board;
- a converging optical system to conduct reproducing information for an information recording plane of a first optical information recording medium having a first protective base plate having a thickness t1 by converging the first light flux from the first light source on the information recording plane of the first optical information recording medium and to conduct recording or reproducing information for an information recording plane of a second optical information recording medium having a second protective base plate having a thickness t2 (t2>t1) by converging the second light flux from the second light source on the information recording plane of the second optical information recording medium;
- comprising:
- the objective lens to converge the first light flux from the first light source or the second light flux from the second light source, wherein a divergent angle or a converging angle of the second light flux from the second light source is different from that of the first light flux from the first light source.
Dependencies are inferred from the claim text.