Abstract: A driver circuit configured to generate a drive signal for an optical source comprises an overshoot controller that provides an amount of overshoot for a given logic state of the drive signal as a function of a duration of at least one previous logic state of the drive signal. The drive signal may alternate between a first logic state associated with a first operating mode of the optical source and a second logic state associated with a second operating mode of the optical source. The overshoot controller may be configured to provide amounts of overshoot for respective instances of the first logic state that are proportional to the durations of their respective immediately preceding second logic states. The driver circuit may be implemented in a heat-assisted magnetic recording system in which the optical source alternates between on and off states associated with respective magnetic write and magnetic read modes.

Abstract: A driver circuit for a laser diode or other optical source comprises a controllable termination for a transmission line coupled between the driver circuit and the optical source, with the controllable termination being switchable between at least first and second termination configurations. The transmission line comprises a first conductor coupled to a first terminal of the optical source and a second conductor coupled to a second terminal of the optical source, and the driver circuit comprises a first current source configured to drive the first conductor, and a second current source configured to drive the second conductor. By way of example, the first termination configuration may comprise an alternating current (AC) termination configuration and the second termination configuration may comprise a direct current (DC) termination configuration.

Abstract: Provided is a recording apparatus including a self-excited oscillation semiconductor laser that has a double quantum well separate confinement heterostructure and includes a saturable absorber section to which a negative bias voltage is applied and a gain section into which a gain current is injected, an optical separation unit, an objective lens, a light reception element, a pulse detection unit, a reference signal generation unit, a phase comparison unit, a recording signal generation unit, and a control unit.

Abstract: A laser diode write driver is described.

Abstract: When a phase shift is to be evaluated, based on a difference between an output from a waveform equalization circuit to equalize an input reproduced signal to a predetermined target equalization characteristic and the target equalization characteristic, the phase shift of the reproduced signal relative to a channel clock, a group delay characteristic with respect to the frequency of the waveform equalization circuit is fixed. Hence, an equalized waveform as an output from the waveform equalization circuit can preserve phase shift information of the inputted reproduced signal to correctly detect the phase shift of the reproduced waveform using the equalized waveform. It is hence possible to realize, with high precision, optimal value learning of various parameters for the recording, reproduction, and servo by use of the phase shift as an index.

Abstract: An optical disk drive controls recording power with high accuracy in accordance with a measured ? value and a target ? value. A system controller of the optical disk drive determines a ? value at which jitter or an error rate becomes minimum, in both an inner radius and an outer radius of an optical disk, and determines a difference between the determined ? value and the target ? value for each of the inner and outer radii. A corrected value for an arbitrary position, arbitrary speed, and an arbitrary temperature is calculated from a difference achieved at the inner radius and a difference achieved at the outer radius, by means of linear interpolation. The measured ? value for the arbitrary position, the arbitrary speed, and the arbitrary temperature is compared with the target ? value after having been corrected, thereby controlling recording power.

Abstract: An optical disk device and recording method of recording data on an optical disk by driving a laser light source with a driving current superimposed with a high-frequency current. The device and method includes a controller for disabling tracking servo and establishing conditions for reproducing a signal from a predetermined region of the optical disk, for generating a tracking error signal by superimposing the high-frequency current varied in amplitude on the driving current for the laser light source, for determining an amplitude of the high-frequency current that provides an optimum quality of the generated tracking error signal, and for recording data on the optical disk by applying the driving current for the laser light source superimposed with the high-frequency current of the determined amplitude.

Abstract: Focus control is performed for an optical disc having at least two data layers. One data layer is located closer than the other to a beam-incident surface of the disc. Maximum levels in positive and negative sides on a characteristic curve of a focus error signal obtained from the disc are obtained for both data layers. First and second focus balance values are obtained based on the maximum levels for the data layers, respectively. It is determined whether a difference between the first and second focus balance values satisfies at least either a first requirement or a second requirement. The first requirement requires that the difference exceed a predetermined threshold value. The second requirement requires that the second focus balance value be smaller than a predetermined threshold value. A focus balance value is selected depending on a result of the determination, for focus control.

Abstract: The invention prevents mark distortion during high-speed recording on an optical disc, thereby improving recording performance. A write pulse signal includes mark periods during which marks 201 are formed and space periods during which no marks are formed. Particular mark periods include a top pulse 101 having first write power Pw; a bias pulse 102 that follows the top pulse 101 and has bias power Pm lower than the first write power Pw; and a last pulse 103 that follows the bias pulse 102 and has second write power Pl lower than the first write power Pw.

Abstract: A disc-shaped information recording medium includes a laminate of recording layers on and from which an information signal can be optically recorded and reproduced from one side of the medium. Data areas are provided in the recording layers, respectively. The information signal can be recorded on and reproduced from the data areas while a laser beam emitted from an optical pickup is applied to the data areas. Optical recording test areas are provided in the recording layers, respectively. A test signal can be recorded on and reproduced from the optical recording test areas to decide optimum power values of the laser beam for signal recording. The test areas are out of overlap as viewed in a direction of propagation of the laser beam.

Abstract: An information processing apparatus includes: a signal reproduction section configured to obtain a reproduced signal from a recording medium by radiating a laser beam emitted by a laser-beam source to the recording medium; and a high-frequency signal superposition section configured to superpose either a first high-frequency signal or a second high-frequency signal having a frequency higher than the frequency of the first high-frequency signal on a driving signal used for driving the laser-beam source, wherein, in a first signal reproduction operation, the high-frequency signal superposition section superposes the first high-frequency signal on the driving signal whereas, in a second signal reproduction operation to measure information on the amplitude of the reproduced signal, the high-frequency signal superposition section superposes the second high-frequency signal on the driving signal.

Abstract: This invention provides accurate control of laser light power in a recording operation to achieve more stable recording operation. An optical disc drive in an embodiment of this invention monitors the power of laser light with a monitor diode and controls the laser light power based on the result of monitoring. The optical disc drive changes data transfer rate (recording frequency) depending on the disc radial position. The optical disc drive controls the gain of the monitor diode across the recording surface depending on the recording frequency. This control improves the accuracy in laser light power control to achieve stable recording operations by precise servo control.

Abstract: There is provided a control device including a recording portion that records data on a disk by shining a laser beam onto a recording surface of the disk, a reading portion that reads the data on the disk, a control parameter computation portion that computes a control parameter, a differential computation portion that computes a differential between the control parameter and a value that is set in advance for the disk, a determination portion that determines whether the differential that the differential computation portion has computed is within a range of a dead band, an output value computation portion that computes an output value for the laser beam, an output control portion that controls the laser beam, a storage portion that stores a plurality of combinations of the dead band and the gain, and a selecting portion that selects one of the combinations of the dead band and the gain.

Abstract: An optical information recording medium (1) includes, on a substrate (50), a ROM layer (20), a RE layer (40), an intermediate layer (30) separating the ROM layer (20) and the RE layer (40), and a cover layer (10) provided in a position farthest from the substrate (50). The RE layer (40) is an information recording layer provided in a position farthest from the light transmitting layer and also is a recording layer of disc type identification information and an individual identification number recorded in a format allowing easier determination as compared to an information recording format used in the layer allowing only readout of information by use of light irradiation. Therefore, it becomes easy to check a disc type in a recording/reproducing device and one recording/reproducing device can be shared with other types of optical disks. Further, disk production becomes easy.

Abstract: The invention discloses an optical recording drive for recording data on an optical carrier such as an optical disk of the DVD or BD format. A radiation source is arranged to emit a write pulse train (80) for writing an optically detectable effect (90) i.e. a pit or mark. Photo detection means (10) detects a first reflected radiation beam pulse (R1) from a start time portion of the write pulse train (80) and generates a corresponding first signal (PS1) indicative of the power in the first pulse, the photo detection means (10) further detects a second reflected radiation pulse (R2) from an end time portion of the write pulse train (80) and generates a corresponding second signal (PS2) indicative of the power in the second pulse. By comparing (e.g.

Abstract: An image formation width calculation circuit and an image formation shift amount determination circuit are provided so that, before a visible image is formed, an effective image formation diameter of an image formation laser spot is measured, and based on the result, a shift amount of the laser spot is adjusted. An optical pickup which forms a plurality of laser spots on an optical disk is also provided. An image formation focus control laser power control circuit and an image formation laser power control circuit are also provided. A focus control laser spot is located ahead of the image formation laser spot.

Abstract: The invention relates to the field of the optical recording of information on a medium, such as an optical disc. To read an optical disc in super-resolution mode, a procedure for optimizing the power of the read laser beam is implemented. This optimization is based on the observation that a correlation exists between the power allowing the disc to be read without risk in super-resolution mode and the amplitude of the read signal which results from the reading of marks having the smallest possible dimension (marks 2 T). The amplitude of the optical disc is measured for several powers of decreasing values of the read laser, the reduction in amplitude is observed. A read power is selected as a function of the power for which a decrease (for example 5%) is noted in the amplitude measured at the start.

Abstract: According to one embodiment, an optical disk device includes types of semiconductor laser diodes configured to emit laser light of different wavelengths, an output control circuit configured to control light output of each semiconductor laser diode, and a composite power source configured to generate voltages required for driving the types of semiconductor laser diodes and operating the output control circuit from a single power source voltage and to selectively output the generated voltages. The composite power source includes an input port to input an external control signal at a time of voltage selection and is configured to change the output voltage stepwise in response to the control signal.

Abstract: The present invention discloses read and write power control methods and system for an optical recording device that records information on an optical disk having read-only areas. The read and write power control methods respectively introduce the steps of determining a specific level of a former power control signal output based on a former power control, and then according to the specific level, setting a predetermined level of a power control signal to induce a present power control for rapidly outputting a proper power of the pick-up head. Accordingly, the level transition of the read/write power control signal can be shortened and even eliminated. An unstable read/write power output for the pick-up head can be avoided.

Abstract: A method for calibrating an initial driving signal for driving an optical pick-up head of an optical disk drive is provided. On one embodiment, said optical disk drive is utilized for reading or writing data on an optical disk, the optical disk comprises a plurality of auto power control areas (APC areas) and a plurality of data areas, and the APC areas and the data areas are interleaved in between. First, in the APC areas, an initial driving signal is used to drive the optical pick-up head to emit laserbeam. A detected level of the laserbeam is then obtained. An update initial driving signal is then calibrated according to the detected level and a target level.

Abstract: An operating current modifying device is provided for a power generating element. The power generating element generates an output power when the operating current is larger than a threshold current in the power generating element. A functional relationship is between the threshold current and the temperature of the electrical device. The operating current modifying device includes a threshold current modifying module, a power modifying module, a current compensating module, and a power control module. The threshold current modifying module receives a temperature signal from the power generating element to output a threshold current modifying signal according to the temperature signal and the functional relationship. The power modifying module receives a power feedback signal from the power generating element and a target power signal to output an operating current modifying signal.