Abstract: A phase shift element has a tiered phase difference pattern portion, in which an inner circular side tiered phase difference pattern portion is continuously connected with an outer circular side tiered phase difference pattern portion based on a phase function curve obtained by a single phase-function with a wavelength having the same value as a reference wavelength ?1 of a first laser light being determined as a designed wavelength ?, formed in annular shapes on one surface thereof. A tier pitch of tiers of the inner circular side tiered phase difference pattern portion is set to a height corresponding to a phase difference of substantially 1? and, on the other hand, a tier pitch of tiers of the outer circular side tiered phase difference pattern portion is set to a height corresponding to a phase difference of substantially m? (where m is a natural number which does not include 0) or a height corresponding to the phase difference of substantially m? by changing a value of m for each step.

Abstract: A recording method for an optical disk drive is implemented as follows. First, at least one of the level of the focusing error signal, the level of the tracking error signal, a wobble synchronization pattern loss, the error rate of demodulating a wobble signal, the frequency of buffer under-run occurrence, the temperature of the drive, the wobble jitter and the level of write power is detected. If at least one detected value exceeds the preset value, the recording will be ceased. Then, the rotation speed of the optical disk drive is decreased, and the recording is resumed with the decreased rotation speed. If at least one of the temperature of the drive, the wobble jitter and the estimated write power exceeds the reset value before recording starts, the rotation speed of the optical disk drive is decreased before recording.

Abstract: An extremely high resolution holographic lens is provided, comprising an interference pattern between light emitted from at least one tiny point source of light such as the tip of an optical fiber, having a diameter in the nanoscale region, and at least one plane or quasi-plane broad light beam. The holographic lens is employed for example in pickups for reading data off of, and writing data upon terabit optical storage mediums and nanoscale resolution microscopic media.

Abstract: A method and apparatus to record data on an optical recording medium include generating a recording waveform having an erase pattern comprising a predetermined pulse having a high level which is higher than an erase power level and having a low level which is lower than the erase power level.

Abstract: The present invention proposes an optical head apparatus provided with light-blocking structure that can reliably prevent nonessential light from reaching the photo detector, without being an impediment to miniaturization and flattening, moreover, without increasing manufacturing cost. In an optical head apparatus, and in a lens holder, light-blocking section is provided that blocks nonessential light from passing outside the effective diameter of objective lens. This light-blocking section is constructed so that it extends only in tracking direction T of objective lens 5. Further, light-blocking face of light-blocking section slants at an angle of 1° or more toward the face orthogonal to the optical axis, consequently, nonessential light is reflected in a direction other than the direction of photo detector.

Abstract: A reproduction-only optical disc has a lead-in area, a user data area, and a lead-out area. Disc related information recorded on at least one of the lead-in area and the lead-out area is recorded by high frequency groove wobbles, and data of the user data area is recorded by pits. Since the high-density reproduction-only optical disc uses the same channels for reproduction signals as a high-density recordable optical disc, the two types of discs are consistent with each other and are compatible with the same disc drives.

Abstract: Embodiments of methods and systems for controlling access to information stored on memory or data storage devices are disclosed. In various embodiments, fluid-mediated modification of information or access to information is utilized. According to various embodiments, data storage devices designed for rotating access are described which include rotation-activated fluid control mechanisms.

Abstract: A disk reproducing apparatus for reproducing a digital audio signal recorded on a DVD or CD has a PLL portion for outputting a synchronizing signal in synchronism with the digital audio signal. When the CD is reproduced at double speed or higher, the PLL portion increases again while seeking tracks, and restores the gain if a predetermined time has passed after the end of seek.

Abstract: An optical pickup device includes a light source unit an optical system which leads a return light beam to a predetermined light-receiving location and includes an object lens focusing each light beam from the light source unit to a recording surface of a corresponding storage medium and a photodetector arranged at the light-receiving location. The light source unit includes a plurality of light sources outputting light beams respectively, the plurality of light sources being arranged in proximity to each other, and a divergence-angle changing unit changing an angle of divergence of a light beam output from at least one of the plurality of light sources.

Abstract: An apparatus is provided for disc rotation control in an optical storage system, which is capable of generating a focusing error signal from light that was reflected by a loaded optical disc. The apparatus includes a focus controller for processing the focusing error signal to obtain a focus output signal, a low pass filter unit for processing the focus output signal by low pass filtering to obtain a filtered signal, a direct current level remover for removing a direct current component of the filtered signal to obtain a warp-indicating signal, and a speed controller for comparing the warp-indicating signal with a predetermined threshold value to determine extent of warping of the optical disc. The speed controller is operable to control the optical storage system so as to limit maximum rotation speed of the optical disc according to result of the comparison made by the speed controller.

Abstract: Substantially all of the laser light emitted from laser chip(s) 11 toward optical disk(s) 17 may be transmitted through polarizing hologram(s) 13 and may thereafter be transmitted through quarter-wave plate(s) 15, and after being reflected at optical disk(s) 17, may again be transmitted through quarter-wave plate(s) 15 and be incident on polarizing hologram(s) 13. Accordingly, where laser light is transmitted twice through quarter-wave plate(s) 15, the direction(s) of polarization thereof may be rotated by 90 degrees before it is incident on polarizing hologram(s) 13. For this reason, even if laser light is p-polarized when it is transmitted through polarizing hologram(s) 13 from laser chip(s) 11, it may be s-polarized when it is again transmitted through polarizing hologram(s) 13 after being reflected from optical disk(s) 17. Laser light, after being made s-polarized, may be diffracted by polarizing hologram(s) 13, which diffracts only s-polarized light.

Abstract: An optical disc of write once type, a method and an apparatus of managing defect information on the optical disc of write once type, e.g., a BD-WO, are provided with a temporary defect management area (TDMA). The method includes preparing the temporary defect management area (TDMA) in which a temporary defect list (TDFL) is recorded as defect management information for managing a defective area on the optical disc, recording the most recent temporary defect list cumulatively with the previous temporary defect list in the temporary defect management area, and recording position information for indicating a position of the most recent temporary defect list in the temporary defect management area along with the temporary defect list to more effectively manage the temporary defect list.

Abstract: A conventional broadband quarter-wave plate has not completely solved the wavelength dependence and has different efficiencies of shifting the phase by 90° depending on the wavelengths, and therefore has a problem that it cannot fulfill the strict specifications on the optical characteristics which are demanded of a wave plate from a viewpoint of the optical efficiency and the like in an optical pickup device compatible with a plurality of different wavelengths.

Abstract: In the case of determination means (10) for determining the quality of a data signal (DS), which data signal (DS) consists of data blocks, wherein each data block is at least two-dimensional in structure and comprises at least two data zones, there are provided validity assessment means (7) for assessing whether data zones of at least one data block are valid or invalid and for generating and outputting validity information (QI) representing the assessment result and validity information processing means (9), which are designed to determine the quality of the data signal (DS) on the basis of the validity information (QI).

Abstract: A method for discriminating between different types of optical discs is intended to apply to an optical storage device with a pick-up head having three beams. A main beam push-pull signal and a sub-beam push-pull signal, both acquired by means of the photo-detector of the pick-up head, are superposed on each other to have an additive push-pull signal, whereas, on subtraction, the difference between the main beam push-pull signal and the sub-beam push-pull signal generates a differential push-pull signal. If the peak-to-peak voltage of the differential push-pull signal is greater than that of the additive push-pull signal, it is judged that the light spots derived from the sub-beams and the main beam of the three beams respectively fall on two contiguous lands and a groove therebetween on an optical disc inside the optical storage device.

Abstract: An optical pickup apparatus includes: first-third light sources; a packaged multiple light source unit for packaging emitting points of at least two of the first-third light sources in one housing; an objective optical system for converging light fluxes emitted by light sources onto information recording surfaces of at least three kinds of optical disks; and a magnification adjusting optical unit having an actuator and a movable lens group and being arranged in an optical path between the packaged multiple light source unit and the objective optical system, wherein the movable lens group is driven by the actuator along the optical axis so as to change a magnification of the objective optical system according to a wavelength of a light flux emitted by the packaged multiple light source unit.

Abstract: A method and apparatus to record data on an optical recording medium include generating a recording waveform having an erase pattern comprising a predetermined pulse having a high level which is higher than an erase power level and having a low level which is lower than the erase power level.

Abstract: Laser light is irradiated from a lateral side of an optical disk (2) set in place to a peripheral side face of the optical disk (2), return light from the peripheral side face irradiated with the laser light is detected, and a displacement of the optical disk (2) is measured based on the detected amount of return light. Also, the focus is adjusted in relation to the information recording surface correspondingly to the measured disk displacement. Thus, a displacement of an optical disk can be measured in an extremely simple manner and with an extremely high accuracy, and information can accurately be recorded or reproduced to or from the optical disk with the focus being controlled.

Abstract: A method for controlling long seeking operation in an optical disc drive is provided. The optical disc drive includes a sled actuator, a pickup head installed on the sled actuator for reading and/or writing data in an optical disc, and a controller for controlling the sled actuator to move together with the pickup head. The method includes the steps of (a) receiving remaining tracks information indicating a number of tracks remained to be crossed by the sled actuator and/or the pickup head; (b) receiving velocity information indicating a velocity of the sled actuator and/or the pickup head; (c) receiving acceleration information indicating an acceleration of the sled actuator and/or the pickup head; (d) driving the sled actuator to move according to the remaining tracks information, the velocity information, and the acceleration information.

Abstract: When an optical storage drive executes a control procedure or operation, a method of handling an interrupt request includes utilizing the optical storage drive to receive an interrupt request from a control circuit; checking whether the interrupt request is a read command; if the interrupt request is a read command, checking whether data indicated by the read command is in a buffer; and if the indicated data in the buffer, transferring the corresponding data to the control circuit from the buffer to respond to the interrupt request.