Abstract: A common objective lens typically used in reading data from different optical data storage media that are responsive to laser beams of different wavelengths, such as CD and DVD is provided. The lens has a refracting surface with inner and outer refracting surface regions. Diffraction gratings are provided in both the inner and outer refracting surface regions with each having a differential optical path function. The inner diffraction grating and at least a part of the outer diffraction grating emit an order of diffracted beams which have different polarities to cancel out any spherical aberrations caused by a change in temperature.

Abstract: A lens driving apparatus includes a lens holder and a driver for providing linear motion to the lens holder along an optical axis of the lens. The driver includes an electromagnetic mechanism, provided at the outer circumference of the lens holder in an enclosing manner, for generating a torque around the optical axis; and a switching mechanism for switching the generated torque to a linear driving force along the optical axis so as to linearly move the lens holders. The driver surrounds the lens holder along the outer circumference to allow a smaller sized lens driving apparatus than that where the lens holder is at a side of the lens driving apparatus. In addition, the switching mechanism prevents the lens holder from moving in the optical axial direction, when power is turned off or even when an external force is applied to the lens holder.

Abstract: An optical head device that converges first and second laser beams having different wavelengths on recording surfaces of first and second optical recording media through a single light converging optical system including an objective lens for recording or reproducing data on the recording surfaces. A refracting surface of the objective lens is divided into two regions, i.e., a central refracting surface region with an optical axis thereof being as a center and an outer circumferential refracting surface region that surrounds an outer circumference of the central refracting surface region. A diffraction grating is formed generally entirely over the central refracting surface region. When recording or reproducing data on the first optical recording medium using the first laser beam, a beam spot is formed with a diffracted beam obtained by the central refracting surface region.

Abstract: An objective lens drive device includes an objective lens, a lens holder holding the objective lens, a fixed side member supporting the lens holder with a plurality of wires in a movable manner, a focusing and tracking drive mechanism, and a tilt drive mechanism for driving the lens holder in a tilt direction. The tilt drive mechanism includes at least a tilt drive coil disposed at one place which is mounted on either side of the lens holder and the fixed side member and at least a tilt drive magnet disposed at one place so as to be opposed to the tilt drive coil on an other side of the lens holder and the fixed side member.

Abstract: A common objective lens typically used in reading data from different optical data storage media that are responsive to laser beams of different wavelengths, such as CD and DVD is provided. The lens has a refracting surface with inner and outer refracting surface regions. Diffraction gratings are provided in both the inner and outer refracting surface regions with each having a differential optical path function. The inner diffraction grating and at least a part of the outer diffraction grating emit an order of diffracted beams which have different polarities to cancel out any spherical aberrations caused by a change in temperature.

Abstract: A lens driving apparatus includes a lens holder and a driver for providing linear motion to the lens holder along an optical axis of the lens. The driver includes an electromagnetic mechanism, provided at the outer circumference of the lens holder in an enclosing manner, for generating a torque around the optical axis; and a switching mechanism for switching the generated torque to a linear driving force along the optical axis so as to linearly move the lens holders. The driver surrounds the lens holder along the outer circumference to allow a smaller sized lens driving apparatus than that where the lens holder is at a side of the lens driving apparatus. In addition, the switching mechanism prevents the lens holder from moving in the optical axial direction, when power is turned off or even when an external force is applied to the lens holder.

Abstract: An optical head device includes a first laser light source that emits a first laser beam with a first wavelength, a second laser light source that emits a second laser beam with a second wavelength which is different from that of the first laser beam, a common objective lens that converges the first laser beam on a recording surface of a first optical recording medium and the second laser beam on a recording surface of a second optical recording medium, a refraction surface that is formed on the common objective lens so as to be divided into a center side refraction surface region around an optical axis of the common objective lens and an outer peripheral side refraction surface region surrounding the center side refraction surface region and a center side diffraction grating that is formed all over the center side refraction surface region and is provided with a number of minute steps in a concentrically circular shape.

Abstract: An optical head device that converges first and second laser beams having different wavelengths on recording surfaces of first and second optical recording media through a single light converging optical system including an objective lens for recording or reproducing data on the recording surfaces. A refracting surface of the objective lens is divided into two regions, i.e., a central refracting surface region with an optical axis thereof being as a center and an outer circumferential refracting surface region that surrounds an outer circumference of the central refracting surface region. A diffraction grating is formed generally entirely over the central refracting surface region. When recording or reproducing data on the first optical recording medium using the first laser beam, a beam spot is formed with a diffracted beam obtained by the central refracting surface region.