Abstract: A lens support mechanism including a semiconductor laser 10 for emitting a laser beam, an optical head enclosure 3 to which the semiconductor Laser 10 is fixed and located, a collimator lens 21 disposed coaxially with the laser beam emitted from the semiconductor laser 10, a resin cylinder 22 formed in a cylindrical shape so as to fix and locate the collimator lens 21 to the inner surface thereof and a cylindrical member 23 fitted to the resin cylinder 22 on a side of the collimator lens 21 opposite to the semiconductor laser 10 and formed so as to be fixed to the optical head enclosure 3. The cylindrical member 23 has almost the same linear expansion coefficient as that of the optical head enclosure 3.

Abstract: A lens support mechanism including a semiconductor laser 10 for emitting a laser beam, an optical head enclosure 3 to which the semiconductor Laser 10 is fixed and located, a collimator lens 21 disposed coaxially with the laser beam emitted from the semiconductor laser 10, a resin cylinder 22 formed in a cylindrical shape so as to fix and locate the collimator lens 21 to the inner surface thereof and a cylindrical member 23 fitted to the resin cylinder 22 on a side of the collimator lens 21 opposite to the semiconductor laser 10 and formed so as to be fixed to the optical head enclosure 3. The cylindrical member 23 has almost the same linear expansion coefficient as that of the optical head enclosure 3.

Abstract: An optical head reproduces optical disks of different disk plate thickness t1 (0.6 mm) or t2 (1.2 mm) by using light beams of two wavelengths and one object lens. An converging element comprises a central portion and outer portion, wherein the central portion has optimum design plate thickness of 0.6*t1 to t1 and the outer portion has optimum design plate thickness of 0.6 mm. By providing a step difference in the converging element, information can be recorded or reproduced for an information medium of disk plate thickness t1 and for an information medium of disk plate thickness t2, in a state having small side lobes. Alternatively, a step difference is provided in the object lens, and optical distance L2 from a second light source to a condensing optical system is set to 80 to 95% of optical distance L1 from a first light source to the condensing optical system. Alternatively, only light of first wavelength is shielded or diffracted in a ring-like shape.

Abstract: Light from a light source (1) is split by an optical splitting means (2) into a main beam and at least two subbeams. A focusing optical system (6) focuses the main beam and the subbeams to the vicinity of an optical disc (7) such that their focal points are different in the direction of the optical axis of the focusing optical system (6) and the direction orthogonal thereto. A detecting means (9) detects relative inclination of the optical disc (7) to the optical axis of the focusing optical system (6) by detecting the spot size on the detecting means (9) of the subbeam reflected off the optical disc (7). Relative inclination of the optical disc (7) to the optical axis of an optical head can thereby be detected with high accuracy without increasing the size or the cost of the optical head.

Abstract: An optical head reproduces optical disks of different disk plate thickness thicknesses t1 (0.6 mm) or t2 (1.2 mm) by using light beams of two wavelengths and one object lens. An converging element comprises a central portion and outer portion, wherein the central portion has optimum design plate thickness of 0.6*t1 to t1 and the outer portion has optimum design plate thickness of 0.6 mm. By providing a step difference in the converging element, information can be recorded or reproduced for an information medium of disk plate thickness t1 and for an information medium of disk plate thickness t2, in a state having small side lobes. Alternatively, a step difference is provided in the object lens, and optical distance L2 from a second light source to a condensing optical system is set to 80 to 95% of optical distance L1 from a first light source to the condensing optical system. Alternatively, only light of first wavelength is shielded or diffracted in a ring-like shape.

Abstract: An optical head reproduces optical disks of different disk plate thickness t1 (0.6 mm) or t2 (1.2 mm) by using light beams of two wavelengths and one object lens. An converging element comprises a central portion and outer portion, wherein the central portion has optimum design plate thickness of 0.6*t1 to t1 and the outer portion has optimum design plate thickness of 0.6 mm. By providing a step difference in the converging element, information can be recorded or reproduced for an information medium of disk plate thickness t1 and for an information medium of disk plate thickness t2, in a state having small side lobes. Alternatively, a step difference is provided in the object lens, and optical distance L2 from a second light source to a condensing optical system is set to 80 to 95% of optical distance L1 from a first light source to the condensing optical system. Alternatively, only light of first wavelength is shielded or diffracted in a ring-like shape.

Abstract: An optical pickup head is provided with a light source, a diffracting means for creating a plurality of diffracted beams, a converging means for focusing the diffracted beams onto an optical storage medium, a beam branching means for branching the plurality of beams reflected by the optical storage medium, and an optical detecting means for outputting a signal corresponding to the amount of light of the received beams. The optical detecting means has main beam light receiving portions and sub-beam light receiving portions. The amount of light of the first or higher order diffracted beams when they are substantially focused on and reflected by a focus plane of the plurality of information recording planes is equal to or greater than the amount of light of the zero order diffracted beam when it is reflected without focusing by a non-focus plane other then the focus plane of the plurality of information recording planes.

Abstract: An optical head reproduces optical disks of different disk plate thickness t1 (0.6 mm) or t2 (1.2 mm) by using light beams of two wavelengths and one object lens. An converging element comprises a central portion and outer portion, wherein the central portion has optimum design plate thickness of 0.6*t1 to t1 and the outer portion has optimum design plate thickness of 0.6 mm. By providing a step difference in the converging element, information can be recorded or reproduced for an information medium of disk plate thickness t1 and for an information medium of disk plate thickness t2, in a state having small side lobes. Alternatively, a step difference is provided in the object lens, and optical distance L2 from a second light source to a condensing optical system is set to 80 to 95% of optical distance L1 from a first light source to the condensing optical system. Alternatively, only light of first wavelength is shielded or diffracted in a ring-like shape.

Abstract: An optical head reproduces optical disks of different disk plate thickness t1 (0.6 mm) or t2 (1.2 mm) by using light beams of two wavelengths and one object lens. An converging element comprises a central portion and outer portion, wherein the central portion has optimum design plate thickness of 0.6*t1 to t1 and the outer portion has optimum design plate thickness of 0.6 mm. By providing a step difference in the converging element, information can be recorded or reproduced for an information medium of disk plate thickness t1 and for an information medium of disk plate thickness t2, in a state having small side lobes. Alternatively, a step difference is provided in the object lens, and optical distance L2 from a second light source to a condensing optical system is set to 80 to 95% of optical distance L1 from a first light source to the condensing optical system. Alternatively, only light of first wavelength is shielded or diffracted in a ring-like shape.

Abstract: An optical pickup head is provided with a light source, a diffracting means for creating a plurality of diffracted beams, a converging means for focusing the diffracted beams onto an optical storage medium, a beam branching means for branching the plurality of beams reflected by the optical storage medium, and an optical detecting means for outputting a signal corresponding to the amount of light of the received beams. The optical detecting means has main beam light receiving portions and sub-beam light receiving portions. The amount of light of the first or higher order diffracted beams when they are substantially focused on and reflected by a focus plane of the plurality of information recording planes is equal to or greater than the amount of light of the zero order diffracted beam when it is reflected without focusing by a non-focus plane other then the focus plane of the plurality of information recording planes.

Abstract: In a objective lens driver, at least one permanent magnet is mounted on a movable member, and plural yokes, each being wound with a coil having its winding axis in the focusing direction, are disposed facing the permanent magnet. The yokes are arranged almost symmetrically about a plane including the center of gravity of the movable member and being perpendicular to the tracking direction. In this structure, even when the movable member moves in the tracking direction, since the permanent magnet (a magnetic field source) also moves with the movable member, the distribution of magnetic flux density that contributes to the drive also shifts according to the movement of the movable member, so that the distribution of magnetic flux density maintains being almost symmetrical about the center of gravity of the movable member. Accordingly, in tilt drive, a constant sensitivity to tilt drive is obtained regardless of the position of the movable member.

Abstract: An optical pickup head is provided with a light source, a diffracting means for creating a plurality of diffracted beams, a converging means for focusing the diffracted beams onto an optical storage medium, a beam branching means for branching the plurality of beams reflected by the optical storage medium, and an optical detecting means for outputting a signal corresponding to the amount of light of the received beams. The optical detecting means has main beam light receiving portions and sub-beam light receiving portions. The amount of light of the first or higher order diffracted beams when they are substantially focused on and reflected by a focus plane of the plurality of information recording planes is equal to or greater than the amount of light of the zero order diffracted beam when it is reflected without focusing by a non-focus plane other then the focus plane of the plurality of information recording planes.