Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
194 words
An optical pickup apparatus composed of: a plurality of emission means (1a, 1b) for emitting laser lights (12a, 12b) of different wavelenghts; a first optical system section (14) for converging and irradiating as a light spot (8a, 8b) said emitted laser lights on a recording medium (10); a second optical system section (15) for leading in one an same optical path the reflected lights reflected on said recording medium from said laser ligths; focussing means (6) for converging in different foci on one and same optical axis said reflected lights according to their respective wavelenghts; luminous intensity attenuating means (5) installed on said optical axis between said optical system sections (14,15) and said focussing means (6); and photo-detector means (7) for detecting said reflected lights converged by said focussing means (6) in said different foci on said one and same optical axis, installed in the neighborhood of the focus farthest from said focussing means among said different foci of said reflected lights, and provided with a plurality of light receiving elements (9, 11) which light receiving faces are installed in one and same plane and which are formed in concentric circles of different diameters.
Claim 2
Dependent Claim
194 words
An optical pickup apparatus composed of: a plurality of emission means (1a, 1b) for emitting laser lights (12a, 12b) of different wavelenghts; a first optical system section (14) for converging and irradiating as a light spot (8a, 8b) said emitted laser lights on a recording medium (10); a second optical system section (15) for leading in one an same optical path the reflected lights reflected on said recording medium from said laser ligths; focussing means (6) for converging in different foci on one and same optical axis said reflected lights according to their respective wavelenghts; luminous intensity attenuating means (5) installed on said optical axis between said optical system sections (14,15) and said focussing means (6); and photo-detector means (7) for detecting said reflected lights converged by said focussing means (6) in said different foci on said one and same optical axis, installed in the neighborhood of the focus farthest from said focussing means among said different foci of said reflected lights, and provided with a plurality of light receiving elements (9, 11) which light receiving faces are installed in one and same plane and which are formed in concentric circles of different diameters.
Claim 3
Dependent Claim
61 words
The optical pickup apparatus as definded in claim 1 wherein said first optical system section (14) is installed in accordance with said different wavelenghts of said laser lights, and comprises collimating lenses (2a, 2b) which transform said laser lights into a parallel pencil or rays and objective lenses (4a, 4b) which converge and irradiate said laser lights on said recording medium.
Claim 4
Dependent Claim
82 words
The optical pickup apparatus as defined in claim 1 wherein said second optical system section (15) is installed in accordance with said different wavelenghts of said laser lights, and comprises objective lenses (4a, 4b) which transform into a parallel pencil of rays said reflected lights of said laser lights on said recording medium and polarizing beam splitters (3a, 3b) which reflect at right angles and leads into one and same optical path said reflected lights transformed into said parallel pencil of rays.
Claim 5
Dependent Claim
47 words
The optical pickup apparatus as defined in claim 1 wherein said focussing means (6) comprises a focussing lens which converges according to the wavelengths in different foci on one and same optical axis the pencil of rays formed by said plural reflected lights of said different wavelenghts.
Claim 6
Dependent Claim
38 words
The optical pickup apparatus as defined in claim 1 wherein said luminous intensity attenuating means (5) comprises a shade which shades the central section of the pencil of rays formed by said plural reflected lights of different wavelengths.
Claim 7
Dependent Claim
56 words
The optical pickup apparatus as defined in claim 1 wherein said luminous intensity attenuating means (5) comprises a filter or the like which shades the intensity in the central section of the optical path of the pencil of rays when said pencil of rays formed of said plural reflected lights of different wavelengths is transmitted therethrough.
Claim 8
Dependent Claim
78 words
The optical pickup apparatus as defined in claim 1 wherein said photo-detector means (7) comprises a small diameter light receiving element (9) which light receiving face is formed in the shape of a circle of a small diameter, and big diameter light receiving elements (11) which light receiving faces are formed in the shape of a ring within which inner diameter are mounted in a concentric manner the light receiving faces of the smaller diameter light receiving faces.
Claim 9
Dependent Claim
108 words
The optical pickup apparatus as defined in claim 7 wherein the outer and inner diameters of said big diameter light receiving elements (9, 11) are set substantially in accordance with the outer and inner diameters of the spread of the reflected lights from said laser lights among the reflected lights of different wavelengths emitted by said plurality of emission means on said recording medium which, after said luminous intensity attenuating means (5) attenuated the intensity of the central section of said optical path, are converged in foci (13 b) between said focussing means and said photo-detector means, and irradiated on said photodetector means spread in a ring shape.