| Patent application number | Description | Published |
|---|
| 20080259750 | Optical pick-up head, optical information apparatus, and optical information reproducing method - An optical information apparatus of the present invention includes: an optical pick-up head including: a light source; a diffraction unit; a condensing unit; a beam splitter; a photodetector; and a tracking error signal generator. An optical recording medium has tracks arranged substantially at a constant pitch. An average of a pitch is tp. When a main beam is placed on the track, a first sub-beam and a second sub-beam are placed between the tracks. The tracking error signal generator performs a differential arithmetic operation with respect to signals output from a light-receiving portion receiving the main beam to generate a first push-pull signal, performs a differential arithmetic operation with respect to signals output from the light-receiving portions receiving the first sub-beam and the second sub-beam to generate a second push-pull signal, and performs a differential arithmetic operation with respect to the first push-pull signal and the second push-pull signal to generate a tracking error signal, in a case where an amplitude of the first push-pull signal obtained at the pitch tp is fluctuated when the light beam is scanned in a direction orthogonal to the tracks of the optical recording medium. | 10-23-2008 |
| 20090040894 | Optical Head And Data Processing Apparatus Including The Same - An optical data processing apparatus reads and/or writes data from/on a data storage medium, in which first and second data storage layer are stacked. The apparatus includes: a light detector including at least one photodetector for generating a light quantity signal; a detecting optical system for guiding reflected light beams from a storage layer; and a signal processor for generating a layer sensing signal from the light quantity signal and determining, by the layer sensing signal, the type of data storage medium. The light detector includes a layer sensing photodetector arranged in view of an of an area of the light detector, and further includes a photodetector which is different from the layer sensing photodetector which receives the reflected light beam to generate a focus signal. | 02-12-2009 |
| 20100091636 | OPTICAL HEAD, AND INFORMATION RECORDING-AND-REGENERATION APPARATUS - An optical head that is restrained from becoming larger, even if it is used for an optical-information recording medium that includes a plurality of information recording layers. In this optical head, a collimating lens is formed by a concave lens disposed on the side of a light source and a convex lens disposed on the side of an objective lens. A collimating-lens actuator moves the convex lens in a direction where a spherical aberration is cancelled which is generated according to the thickness of a light transmission layer up to an information recording layer of the optical-information recording medium. An aperture stop is provided on the side of the collimating lens with respect to the objective lens, and the aperture stop is located near the focal position of the convex lens on the side of the objective lens. | 04-15-2010 |
