摘要:
A method of detecting a reproduction signal from an optical disc. A light beam reflected from a recording surface of an optical disc is divided into a central light beam portion and outer light beam portions in a direction corresponding to a radial direction of the optical disc. The central light beam portion and outer light beam portions are detected and a first detection signal from the central light beam portion and a second detection signal from at least one of the outer light beam portions are output. The amplitude of at least one of the first and second detection signals is adjusted and the reproduction signal is detected by subtraction between the first detection and second detection signals so that where reproduction is carried out on an optical disc having a varying track width the reproduction signal is improved.
摘要:
An optical recording medium having groove tracks and land tracks, first wobbles formed along both sidewalls of each of the groove tracks, second wobbles formed along both sidewalls of each of the land tracks and which are independent of the formation of the first wobble. A middle portion is formed at a predetermined position on each of the sidewalls between adjacent pairs of the land and groove tracks. This optical recording medium can significantly reduce the non-recordable area as compared to conventional optical recording media, resulting in a great improvement in recording density.
摘要:
A method of detecting a servo error, an apparatus therefor, a disk which maintains quantity of a servo error signal, a method of controlling a servo of an apparatus for recording data on and reproducing data from a disk, a method of detecting the tracking error, and a method of detecting tilt error of the apparatus. The apparatus for recording data on and reproducing data from the disk in which a recording area is divided into sectors, each sector has a header for indicating an address, each header has a first header and a second header which are recorded to deviate from the center of the track in opposite directions, and the first header and the second header have address areas in which the addresses of sectors are recorded and synchronous signal areas in which synchronous signals for detecting the address signals recorded in the address area are recorded. As a result, it is possible for the recording/reproducing apparatus to stably control a servo therein and maintain an optimal recording/reproducing state since the apparatus for detecting the servo error correctly detects the servo error state of the disk.
摘要:
An error signal detecting apparatus for an optical recording/reproducing apparatus, the error signal detecting apparatus including a photodetector to receive light reflected and diffracted by a recording medium, and a signal processor to detect an error signal by calculating a detection signal of the photodetector. The photodetector includes a plurality of light receiving areas to independently receive light of a light area in which the profile of the light changes to the opposite profile according to the tangential tilt of the recording medium. The signal processor detects a tangential tilt error signal from detection signals of the light receiving areas. Thus, a signal output from the error signal detecting apparatus does not change when a shift is generated in the objective lens or the distance between the objective lens and the disc is deviated from the on-focus position. Also, a change in the profile of the light beam according to a relative tangential tilt with respect to the objective lens of a recording medium in land/groove format can be properly detected so that an accurate tangential tilt error signal can be detected.
摘要:
A method of detecting a servo error, an apparatus therefor, a disk which maintains quantity of a servo error signal, a method of controlling a servo of an apparatus for recording data on and reproducing data from a disk, a method of detecting the tracking error, and a method of detecting tilt error of the apparatus. The apparatus for recording data on and reproducing data from the disk in which a recording area is divided into sectors, each sector has a header for indicating an address, each header has a first header and a second header which are recorded to deviate from the center of the track in opposite directions, and the first header and the second header have address areas in which the addresses of sectors are recorded and synchronous signal areas in which synchronous signals for detecting the address signals recorded in the address area are recorded, includes a reproducing signal generator for generating a reproducing signal including sum signals V1 and V2 of radial pairs, a sum signal RF_sum, and a push-pull signal RF_pp from an optical signal reflected from the disk, a header area detector for generating a header area signal including a header area from the reproducing signal received from the reproducing signal generator, a first synchronous signal level detector for receiving the output of the reproducing signal generator and detecting a magnitude Ivfo1 of a first synchronous signal in the first header by being synchronized with the header area signal received from the header area detector, a second synchronous signal level detector for receiving the output of the reproducing signal generator and detecting a magnitude Ivfo3 of a second synchronous signal in the second header by being synchronized with the header area signal received from the header area detector, and a balance calculator for calculating the balance of the magnitude Ivfo1 of the first synchronous signal detected by the first synchronous signal level detector and the magnitude Ivfo3 of the second synchronous signal detected by the second synchronous signal level detector. As a result, it is possible for the recording/reproducing apparatus to stably control a servo therein and maintain an optimal recording/reproducing state since the apparatus for detecting the servo error correctly detects the servo error state of the disk.
摘要:
An optical pickup compatible with a plurality of optical recording media each using light of a different wavelength. The optical pickup includes at least one light source, an objective lens, and a light detector. The objective lens has an inner area, an annular lens area and an outer area such that the annular lens area divides the inner area from the outer area and has a ring shape centered at a vertex. The inner area, the annular lens area and the outer area have aspherical surface shapes to focus light transmitted through the inner area and the outer area into a single light spot by which information can be read from the information recording surface of a relatively thin first optical recording medium and scatter light transmitted through the annular lens area located between the inner area and the outer area so that information cannot be read from the information recording surface of the first optical recording medium, during reproduction of the first optical recording medium. The inner area and the annular lens area transmit light into a single light spot by which information can be read from the information recording surface of a relatively thick second optical recording medium and scatters light transmitted through the outer lens area so that information cannot be read from the information recording surface of the second optical recording medium, during reproduction of the second optical recording medium.
摘要:
An optical pickup device which is capable of reproducing and recording information from/onto at least two kinds of discs having different thicknesses includes a light source, an objective lens provided along the light path from the light source facing the plane of a disc and having a predetermined effective diameter, a beam splitter provided between the objective lens and the light source, and a photodetector for detecting the beam split from the light splitter and reflected from the disc, wherein the photodetector has a first detection region and a second detection region provided in the peripheral portion of the first detection region. The optical pickup device is simplified and the manufacturing cost therefor is low. Also, by reducing the spherical aberration effect for the light, discs having different thicknesses can be used for a single disc drive.
摘要:
A focus error detector for detecting a signal representing a degree of a focus error of an objective lens with respect to an optical disk in an optical pickup, in order to eliminate errors due to an optical axis shift or tilt of the reflected light reflected from the optical disk, includes a diffraction device for diffracting and splitting the reflected light reflected. The focus error detector a critical angle reflector having critical angle reflecting planes for reflecting the two diffracted light rays at two critical angles, two bi-segmented photo-detectors for receiving the two diffracted light rays reflected from the critical angle reflector, respectively, and detecting signals depending on the received light amount, and a circuit for differentiating and summing each signal of the two bi-segmented photo-detectors so as to offset the light amount difference due to the tilt or shift of the reflected light and outputting a desired signal. Therefore, only an original focus error signal is output, irrespective of an optical shift or tilt of the reflected light, so that malfunction of the optical pickup is prevented and clean recording and reproduction is enabled.
摘要:
An optical pickup for an optical magnetic disc includes a light source, a grating for diffracting the light into a main light beam and auxiliary light beams, a plurality of magnetic dipole tips arranged above the optical magnetic disc so as to interact with the magnetic signal stored in the optical magnetic disc. Also, a plurality of mirror members each attached to the rear of each magnetic dipole tips are for reflecting the light incident on the mirror member, and a photodetector for detecting track errors and the stored information by receiving the light reflected from the mirror members are provided, thereby detecting the error signal and reproducing information by the interaction with the magnetic dipoles of the disc so that the recording density can be increased without increasing the conventional land and groove areas in the disc.
摘要:
A focus error detector for detecting a focus error of an objective lens with respect to an optical disk. The focus error detector includes a beam splitter for splitting light reflected from the optical disk. Two critical angle prisms having critical angle reflecting surfaces are included for respectively reflecting the light rays from the beam splitter at the respective critical angles onto two bisectional photo-detectors. The bisectional photo-detector generates detecting signals responsive to the amount of light received. The detecting signals are differentiated and added in a direction offsetting a shift or tilt of the reflected light. Accordingly, only the focus error signal is detected, irrespective of the tilt and shift of the optical axis of the reflected light. Thus, malfunction of an optical pickup is prevented, thereby providing for the uncorrupted recording and reproduction of data.