摘要:
In an information recording/reproducing apparatus, a light beam emitted from a semiconductor laser is guided to a beam splitter. The light beam passing through an incident surface of the splitter is splitted into first and second light beam by a beam splitting layer. The first beam passing through the splitting layer is emerged from a first emerging surface and guided to an optical disk. The first light beam after being reflected from the optical disk is returned to the first emerging surface and passes through the first emerging surface. The returned first light beam passed through a second emerging surface and defected by a detector so that a retrieving signal is generated from a detector. The second light beam reflected from the beam splitting layer is directed to a concave mirror of the splitter and is converged on a mirror detector through a third emerging surface so that a mirror signal for controlling the semiconductor laser is detected.
摘要:
An optical head device adapted to be optically coupled to an optical disk includes a light-source laser and an objective lens optically coupled thereto. This lens receives an output light of the light source, and causes it to be projected onto the optical disk to form a focused spot thereon. Photodetectors which are arranged near the light-source laser are optically coupled to the lens in one optical path so that they are responsive to a light component which is reflected from the optical disk toward the photodetectors by way of the objective lens. A beam-shaping prism is located between the lens and a group of the light source and the photodetectors in the optical path. When the laser output light travels toward the lens, the prism reshapes the light into a predetermined isotropic beam profile. When the reflected light from the optical disk propagates reversely along the same optical path to enter the beam-shaping prism, this prism permits such an incident light to pass through itself toward the photodetectors.
摘要:
In a data recording/reproducing apparatus, a DC motor is provided for rotating an optical disk. A recording/reproducing head is driven to move over the disk linearly in the radial direction of the disk, thereby defining a plurality of data-storing tracks on the disk. A motor control section is provided for controlling the rotation of the disk so as to change the angular velocity of the disk when the head tracing is changed among the track groups. While the head is tracing the tracks included in the same track group, the rotation of the disk is made constant so that the disk rotates at a constant angular speed.
摘要:
An optical-disk system is disclosed which comprises an optical-disk rotating in accordance with constant linear velocity technique, a signal input device for producing an information signal digitally encoded, and address generator for generating an address signal, an interleave circuit for commonly leaving both the information signal and the address signal, and a write controller for modulating a write beam incident to the optical-disk in response to the output signal from the interleave circuit and for forming at least one sector including both the commonly interleaved signals on the optical-disk.
摘要:
An optical head device adapted to be optically coupled to an optical disk includes a light-source laser and an objective lens optically coupled thereto. This lens receives an output light of the light source, and causes it to be projected onto the optical disk to form a focused spot thereon. Photodetectors are optically coupled to the lens in one optical path so that they are responsive to a light component which is reflected from the optical disk toward the photodetectors by way of the objective lens. A beam-shaping prism is located between the lens and a group of the light source and the photodetectors in the optical path. When the laser output light travels toward the lens, the prism reshapes the light into a predetermined isotropic beam profile. When the reflected light from the optical disk propagates reversely along the same optical path to enter the beam-shaping prism, this prism permits such an incident light to pass through itself toward the photodetectors.
摘要:
An optical head apparatus includes a stationary optical system having a light source and a detector for detecting light reflected by a recording medium, which stationary optical system is arranged at a position fixed to the recording medium. Plural objective lenses for focusing/irradiating light emitted from the light source onto the recording medium are arranged on a rotating blade which is provided to be rotatable in a direction parallel to the recording medium. By controlling the waveform of a current to be supplied to a tracking coil, the blade is rotated and a desired one of the objective lenses is located on an optical axis of the light irradiated onto the recording medium.
摘要:
An optical disk apparatus includes a semiconductor laser for emitting a light beam, and an automatic power control or APC circuit for driving the laser. A compound prism structure is optically coupled to the laser in an optical head section, and defines a first optical path for causing a front laser light to be projected onto a rotating optical disk and guiding a reflected light therefrom toward a first photodetector, and a second optical path for guiding a part of the reflected light toward a second photodetector. An output signal of the first photodetector is used to generate a reproduced information signal. An output signal of the second photodetector is fed back to the APC circuit as a front light monitor signal. A part of a laser control signal internally generated in the APC circuit is supplied through a wiring line to a noise reduction circuit as a laser noise monitor signal. The noise reduction circuit subtracts this noise monitor signal from the reproduced information signal to provide a noise-suppressed information signal.
摘要:
Disclosed is an optical head comprising a light source for emitting a light beam having a predetermined wavelength, a light source driving part for driving the light source, a monitor light detector for detecting the light amount of the light beam emitted from the light source, an objective lens for collecting the light beam on a predetermined position of the optical disc, a light receiving element for receiving the light beam reflected from the optical disc so as to convert the received light beam into an electric signal, a base having an open portion and holding an optical member for guiding the light beam in the open portion in a manner to form an optical path of the light beam ranging from the light source to the objective lens, and holding means for holding the monitor light detector within the open portion in parallel to the optical path so as not to interfere with the light beam. The particular construction permits providing a miniaturized and thin optical head capable of overcoming the mounting layout of the members.
摘要:
An optical head comprising two light sources, a beam splitter, and two photodetectors. The first light source emits a first light beam to be applied to the recording surface of a first-type optical disk. The second light source emits a second light beam to be applied to the recording surface of a second-type optical disk. The first light beam and the second light beam intersect with each other at an angle other than 90.degree.. The beam splitter is provided at the intersection of the first and second light beams. The beam splitter guides both light beams in a common optical path which extends to the recording surface of either optical disk. The beam splitter guides the first light beam reflected from the first-type optical disk toward the first light source, and the second light beam reflected from the second-type optical disk toward the second light source. The first photodetector detests the first beam reflected from the first-type optical disk. The second photodetector detests the second beam reflected from the second-type optical disk.