Abstract: A method for controlling the rotation speed of an optical storage device. In the first mode, a first signal is produced, and in the second mode, a second signal is produced. In one mode, a first pulse of a first voltage and a second pulse of a second voltage are sent to the motor, which causes the motor to produce a first armature current and a second armature current. In another mode, a DC signal of a third voltage is produced, which causes the motor to produce a third armature current. The armature currents are detected, and test voltages are outputted. The first and second voltages, and the first and second test voltages are used to find a motor coefficient. The third voltage, the motor coefficient, and the third test voltage are used to calculate a motor rotation speed. The calculated speed is used to control the real motor speed.

Abstract: An optical disc recording apparatus 100 comprises a temperature detecting circuit 141 for detecting a temperature of an optical disc 200 and corrects a laser power for discoloration a discoloration layer of the optical disc 200 in accordance with the temperature detected by the temperature detecting circuit 141 in order to cancel a change in the temperature of the optical disc 200. The optical disc recording apparatus 100 can record a high quality visible image on an optical disc without a printer.

Abstract: A method, an optical disk drive and a calibration system for modifying a 2T write strategy to improve recording quality. The method includes driving the optical disk drive for burning a test odd mark and a test even mark on an optical disk, detecting signal waveforms associated with the test odd mark and the test even mark, adjusting a plurality of writing periods used for forming an even mark according to the signal waveform of the test even mark, and adjusting a plurality of writing periods used for forming an odd mark according to the signal waveform of the test odd mark without utilizing the adjusted writing periods for the even mark.

Abstract: Providing an objective lens with a large numerical aperture (NA), the present invention records or plays conventional optical disks such as CDs and DVDs at high light usage efficiency, using an optical head capable of recording or reproducing high-density optical disks. A diffraction optical element (8) is disposed in a light path of a first light beam of a first wavelength ?1 (400 nm to 415 nm) and a second light beam of a second wavelength ?2 (650 nm to 680 nm). And, the present invention principally emits 5th order diffracted light with respect to the first light beam, and principally emits 3rd order diffracted light with respect to the second light beam, from the diffraction optical element (8). Thus, a high diffraction efficiency of substantially 100% can be obtained with respect to both wavelengths.

Abstract: A wobble signal extraction circuit for extracting a wobble signal from a first optical disk signal containing a wobble signal component caused by a wobble formed on a surface of an optical disk and a second optical disk signal containing a wobble signal component of a reversed phase to that of the first optical disk signal, wherein signal level fixing sections (24a; and 24b) fix the first and second optical disk signals to a predetermined level when a discontinuity of the wobble is detected.

Abstract: An optical disk apparatus includes a tilt detection unit detecting the tilt value of an optical disk medium with respect to an optical system. A tilt compensation unit compensates for the tilt of the optical disk medium by adjusting a relative angle between the optical system and the optical disk medium according to the tilt value detected by the tilt detection unit. A tilt detection error estimation unit estimates tilt detection error of the tilt detection unit with respect to a radial position of the optical disk medium at which information is recorded/reproduced by the optical systems by referring to tilt values that are previously detected at a plurality of radial positions of the optical disk medium by the tilt detection unit. The tilt compensation unit has a correction unit that corrects the tilt value according to the tilt detection error estimated by the tilt detection error estimation unit.

Abstract: It is an object of the present invention to improve reliability of defect management. By providing a plurality of management data areas each including a defect management area typically in a lead-in zone of a disc inner-side region enclosed by a circumference having a predetermined radius on a disc-shaped recording medium, reliability of the defect management can be obtained. In addition, by placing a plurality of the defect management areas (information areas Info1 and Info2) at locations, which are separated from each other in the radial direction of the disc-shaped recording medium, sandwiching a recording/reproduction condition adjustment area OPC having a relatively large size, the reliability of the defect management areas can be further improved.

Abstract: A method of determining the time for executing optimal power calibration in an optical drive. First, relationships between values of a driving signal and ambient temperatures of the optical drive are recorded in look up table in a memory. According to the look up table, mappings from the values of a driving signal output by a compensator to the ambient temperature of the optical drive can be obtained. When the ambient temperature of the optical drive is higher than a predetermined temperature, an optimal power calibration is executed.

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: An optical information recording medium 10 includes a first substrate 11, a second substrate 12 disposed in parallel with the first substrate 11, and an information layer 20 disposed between the first substrate 11 and the second substrate 12, and the information layer 20 includes a recording layer 23 and inorganic layers (lower side interface layer 22 and upper side interface layer 24) adjacent to the recording layer 23. The recording layer 23 is changed between at least two different states, which are discernable optically, by irradiation with a laser beam 14 incident from the first substrate 11 side. The inorganic layer contains a nitride of SixGe1-x (where 0.3?x?0.9) as a main component. The present invention provides an optical information recording medium capable of recording/reproducing information with satisfactory reliability even in recording/reproducing with a light beam having a short wavelength or in recording/reproducing with respect to a plurality of information layers.

Abstract: In a CLV(constant linear velocity) or MCLV(substantially constant linear velocity)-type optical disk apparatus, instability of servo at inner and outer circumferences of an optical disk is prevented by adjusting a servo-loop gain of tracking servo control or focus servo control in accordance with the radial-direction position of an optical spot, i.e., in accordance with the rotation frequency of the optical disk.

Abstract: A motor control system comprises a motor controller and a clamp apparatus and is used for controlling a motor apparatus. The motor controller is used for generating a motor control output according to a reference signal and a feedback signal from the motor apparatus. The clamp apparatus is used for receiving the motor control output and has a clamp function for clamping the motor control output. The clamp apparatus determines whether the clamp function should be activated to clamp the motor control output within an acceptable clamp range according to at least one motor stability signal. When the motor stability signal indicates that the motor apparatus has been in a stable state, the clamp apparatus clamps the motor control output from the motor controller in the acceptable clamp range, so as to avoid an abnormal motor control output resulting from external sudden change.

Abstract: A servo error signal generation circuit comprises a first sampling unit for sampling first detection signals at first sampling timings, a second sampling unit for sampling second detection signals at second sampling timings which are obtained by periodically thinning out the first sampling timings, an AD converter for analog-to-digital converting the data sampled by the first and second sampling units, and a completion unit for completing the sampling date of the timings which have been thinned out by the sub sampling timing generator, for the data which have been sampled by the second sampling unit and outputted from the AD converter.

Abstract: The present invention comprises an apparatus and method for recording information on a multi-layer diffractive optics memory to extend storage capacity. A composite mirror device comprises a plurality of sets of mirror elements. Each one of the mirror elements of the sets is configured to direct a reference beam to a point of the multi-layer memory at one of a plurality of angles. A plurality of planes is associated with the plurality of sets. There is one plane per set, each plane being defined for each of the sets of mirror elements so that the paths formed from the mirror elements of the set to the point lie in the plane. Each of the planes is separated from its neighbor by an angle selected to avoid crosstalk.

Abstract: A method of managing defects on a write-once optical recording medium having at least one recording layer is disclosed. The method of managing defects on the at least one recording layer comprises the steps of allocating at least one replacement area and a plurality of temporary defect management areas to the optical recording medium, wherein the temporary defect management areas are separately provided, and recording defect management information on at least one of the plurality of temporary defect management areas.

Abstract: A temperature sensor (131) detects a temperature of a spindle motor (121) of a rotary drive unit (120) for rotating a disk-shaped recording medium (1), and a temperature information acquiring unit (134A) acquires the temperatures as temperature information. An eccentricity detector (132) detects a drive voltage level, and an eccentricity information acquiring unit (134B) acquires the drive voltage level as eccentricity information. When a determining unit (134C) determines that the temperature is higher than a predetermined temperature or that the drive voltage level is higher than a predetermined voltage, a servo controller (133) switches a rotation mode from constant liner velocity to constant angular velocity. That enables stable information processing over a long time with a simple strucure for constant linear velocity.

Abstract: At least one detection area on an optical storage medium is allocated for data storage first, and then the detection area is set to a defect detection mode of either write detection or write verification, depending on the number of defects stated in a previous defect record. If the detection area is the write detection mode and the number of accumulated defects exceeds a default threshold value, the detection area would be configured anew and thereby set to a defect detection mode of write verification.

Abstract: A phase locked loop (PLL) for generating an output signal according to an input signal is disclosed. The PLL of the present invention includes a detector for generating a detection signal according to the logical difference between the input signal and a feedback signal, a signal mixer electrically connected to the detector for generating a control signal according to the detection signal and a mixing reference signal, a filtering device electrically connected to the signal mixer for generating an adjust signal according to the control signal, a controllable oscillator electrically connected to the filtering device for generating the output signal according to the adjust signal, and a frequency divider electrically connected to the controllable oscillator for generating the feedback signal and the mixing reference signal according to the output signal. The frequency of the output signal is at least twice the frequency of the input signal.

Abstract: A disc type determining apparatus in a disc recording and reproducing apparatus in which vibrations generated by rotations of a disc occur in a focus and tracking control actuator includes an error gain adjusting unit, which adjusts an amplitude of a focus and tracking error in order to maintain a constant amplitude of the focus and tracking error; a loop gain adjusting unit which compares the closed loop phase of the focus and tracking control loop and a predetermined reference closed loop phase, and maintains a constant gain of the focus and tracking control loop; a vibration measuring unit which measures vibrations using the adjusted error and the output of a controller; and a disc type determining unit which extracts a predetermined signal to determine the type of a disc using the measured vibrations, measures the deflection, eccentricity, and mass eccentricity of a disc using the extracted signal.

Abstract: An objective lens drive having an optical axis adjustment function. An objective lens is supported by a lens holder, and the lens holder is supported on a suspension holder by way of a suspension. The suspension holder is supported so as to be rotatable about an axis extending in a direction in which the suspension extends, whereby the suspension holder is supported laterally by means of multilayer piezoelectric elements. When a drive voltage is applied to the multilayer piezoelectric elements, the piezoelectric elements are displaced vertically, whereupon the suspension holder is rotated about the axis, to thus adjust the optical axis of the objective lens.