Abstract: In one embodiment of the present invention, an optical pickup for writing and reading data on an optical storage medium comprises a diffractive element for diffracting a light beam to split it into multiple light beams. The diffracted light beams includes a zero-order diffracted light beam for writing data on a track of the land or the groove of the optical storage medium and non-zero-order diffracted light beams for reading the data from the track. The diffractive element has first and second diffraction gratings that have mutually different grating vector directions and pitches. The first diffraction grating forms light beam spots on the same track by the non-zero-order and zero-order diffracted light beams. The second diffraction grating forms a light beam spot to extend to both sides of said track, or forms a light beam spot on one side of said track, by the non-zero-order diffracted light beams.

Abstract: A magnetic head slider includes a near-field light generator, an incorporated heater is activated to thermally-expand the magnetic head slider so that a first protrusion is generated on the air bearing surface, and a second protrusion protruding from the first protrusion is generated by a thermal expansion of the near-field light generator. A standard signal is written to a recording medium with a predetermined magnetization. A relation between a residual magnetization of the standard signal and a power of the heater is obtained by lowering the magnetization of the standard signal by heating the recording medium with the near-field light while light output of laser light is maintained to be constant and the power of the heater is varied. Further, a relation between the first spacing and the residual magnetization is obtained.

Abstract: A focus search is performed on a mounted optical-disc recording medium once the optical-disc recording medium has been mounted in an optical disc device. The type of the mounted optical-disc recording medium is determined on the basis of results of the focus search. When a determination has been made that the mounted optical-disc recording medium is a multilayer optical-disc recording medium having three or more recording layers, a playback power is for an optical-disc recording medium being of a specification identical to the multilayer optical-disc recording medium and having one or two recording layers. A playback operation at the set playback power is used to read optical disc information from the mounted optical-disc recording medium, the optical disc information indicating the type of the mounted optical-disc recording medium.

Abstract: An optical disc drive according to the present invention includes: a laser light source 2 for emitting a laser beam; a photodetector 10 for detecting a signal that has been supplied from an optical disc 100; and an optical system 200 for irradiating the optical disc 100 with the laser beam and guiding the light reflected from the optical disc 11 to the photodetector 10. The drive further includes a memory 300 for storing information defining a relation between the output value of the photodetector 10 and the output power of the laser light source 2 when the laser light source 2 is emitting the laser beam but the light reflected from the optical disc 100 fails to reach the photodetector 10; and a control section 400 for controlling the output power of the laser light source 2 based on the information stored in the memory 300 and the output of the photodetector 10 when the laser light source 2 is emitting the laser beam but the light reflected from the optical disc fails to reach the photodetector 10.

Abstract: In write power adjustment for an optical disc having a plurality of information storage layers, data of trial writing is varied by the influence of layers other than a target layer. It is difficult, therefore, to determine optimal write power. A modulation M[m] is obtained from a reproduction signal amplitude of a signal subjected to the trial writing performed with use of write powers Pw[m] (m being an integer) of a plurality of kinds. At least an optimum write power intercept Pint_opt is determined by fitting a relation between the Pw[m] and the M[m] by a modulation characteristic formula M=Masy×(1?(Pint?Pasy)/(Pw?Pasy)) having an asymptotic modulation Masy, a write power intercept Pint, and an asymptotic write power Pasy as parameters. Approximation accuracy by the fitting and/or quality of the trial writing signal are evaluated with use of at least the M[m], the modulation characteristic formula, and the Pint_opt.

Abstract: An optical disc device includes an optical source for emitting an optical beam, an incident intensity control circuit for controlling an intensity of the optical beam emitted from the optical source, an objective lens for focusing the optical beam on an optical disc, an optical detector for receiving the optical beam reflected from the optical disc, and a servo signal generation circuit for generating a focus error signal from the optical detector, by this configuration, the optical beam is varied once to a third optical beam intensity to be present in between a first optical beam intensity and a second optical beam intensity when varying from the first optical beam intensity up to the second optical beam intensity different from the first optical beam intensity, and the incident intensity control circuit is controlled such that the variation of focus error signal is not exceeded over a predetermined range.

Abstract: With a large capacity of an optical disk and high-speed recording, a frequency of a recording signal is increased and a pulse width is narrowed. In the case that a laser is driven by a signal having the short pulse width, unfortunately the high-speed recording is hardly performed to an optical disk when a rise time and a fall time of the optical pulse are lengthened. During user data recording, a bottom driving current is set to a second bottom driving current value that is a current value of a threshold or less, so that the rise time and the fall time of the optical pulse can be shortened to perform the high-speed recording of the optical disk.

Abstract: The present invention is related to a method and a reading device (1) for retrieving information from an optical record carrier (10) in which the read power level of a radiation beam (3) for scanning the optical record carrier is set in dependence on the read-out speed. The invention is also related to a record carrier for use with such a method and a reading device.

Abstract: An information recording apparatus carries out DC writing on a section B to change a reflectivity from a recording surface to display a visible character or image. Next, the apparatus writes record data on each of sections A to C under a special recording condition. The special recording condition is a recording condition that: makes excellent the recording characteristics of each of the sections A to C after the record data has been recorded, and sets the pulse width of a write signal for writing a shortest mark to be shorter than an optimum pulse width.

Abstract: This invention provides an optical disc drive with more accurate and stable power control for a laser light source. An optical disc drive in an embodiment of this invention includes a monitor photodetector for receiving laser light emitted by a laser light source to monitor the laser light power. The monitor diode is a photodetector for generating an electric signal corresponding to the laser light power. A laser light controller controls drive current to the laser light source based on a result of measurement by the monitor diode. The optical disc drive measures output variations of the monitor diode and controls the gain of the monitor diode based on the result of the measurement. This gain control improves accuracy and stability in laser light control so that stability in recording/reading can be attained.

Abstract: A recording device includes: a recording unit that records information in a recording layer of an optical recording medium through laser beam emission performed based on a laser driving pulse; and a control unit that reads out setting information of a recording laser power and a laser driving pulse of a past that are stored in correspondence with an optical recording medium set as a recording target from a setting information storing area, allows the recording unit to perform test writing for a test writing area of the recording layer of the optical recording medium using the read out setting information of the past and to reproduce a test writing portion, and performs a setting process in which recording laser power and a laser driving pulse are set based on a result of the test writing and the reproduction.

Abstract: A hologram recording and reproducing device controls an optical beam output from an external cavity semiconductor laser to improve a diffraction efficiency. The hologram recording and reproducing device includes an external cavity laser, a photodiode, a laser drive circuit and a laser diode controller. The external cavity laser has a laser diode adapted to emit an optical beam that is used to generate data light and reference light with which a hologram recording medium is irradiated. The photodiode detects the amount of the optical beam output from the external cavity laser. The laser drive circuit supplies a current to the external cavity laser. The laser diode controller controls the laser drive circuit to ensure that a value obtained by integrating the detected intensity of the optical beam with respect to time over a predetermined period is equal to predetermined recording energy.

Abstract: A writing method for an optical disk drive includes receiving a command to write a disc; implementing an optimum power control (OPC) test for a predetermined data transfer rate to obtain a relation of a beta parameter to writing power; acquiring a writing power for the predetermined data transfer rate with a target beta parameter; calculating the energy area ratio of writing strategies for every data transfer rate; multiplying the energy area ratio by the writing power for the predetermined data transfer rate to produce the writing power for every data transfer rate; and compensating the writing power with automatic writing control.

Abstract: According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.

Abstract: According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.

Abstract: According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.

Abstract: According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.

Abstract: According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.

Abstract: According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.

Abstract: A recording apparatus includes: a recording device for recording data onto a recording medium by applying a laser beam whose power can be adjusted; a first controlling device controlling the recording device to record calibration data while adjusting power; a first detecting device detecting calibration data recording quality; a second detecting device detecting push-pull signal amplitude by reading the calibration data; a first calculating device calculating a power by which the recording quality is desired quality, as a first optimum power; a second calculating device calculating a power by which the amplitude of the recorded push-pull signal satisfies a first condition and by which the recording quality satisfies a second condition, as a second optimum power, if the push-pull amplitude fails the first condition; and a second controlling device controlling the recording device to start recording record data by applying the laser beam with the first or second optimum power.

Abstract: A recording method for an optical disc and an optical disc device are provided. In one embodiment of the present invention, delay at upward transition of laser diode output driven by a recording pulse can be compared with a predetermined reference value; when the delay is larger than the predetermined reference value, the delay at the upward transition can be compensated by adjusting the recording pulse through a pulse of a reserved output channel; and data can be recorded in an optical disc by driving the laser diode by using the adjusted recording pulse. The amount of delay at the upward transition can be detected through a front photo detector of the laser diode; and the comparison and the compensation can be carried out when fast recording more than specified performance on the optical disc is requested.

Abstract: An apparatus for recording and reproducing an information signal on and from an optical disc includes a memory. The information signal is written into the memory. The information signal is read out from the memory. An optical head generates a laser beam in response to the readout information signal, and applies the laser beam to the optical disc to record the readout information signal on the optical disc. A test signal is recorded on a position of the optical disc near a recording position thereof via the optical head during the writing of the information signal into the memory. The test signal is reproduced from the optical disc. The reproduced test signal is evaluated to generate an evaluation result An intensity of the laser beam is optimized in response to the evaluation result.

Abstract: An apparatus for recording and reproducing an information signal on and from an optical disc includes a memory. The information signal is written into the memory. The information signal is read out from the memory. An optical head generates a laser beam in response to the readout information signal, and applies the laser beam to the optical disc to record the readout information signal on the optical disc. A test signal is recorded on a position of the optical disc near a recording position thereof via the optical head during the writing of the information signal into the memory. The test signal is reproduced from the optical disc. The reproduced test signal is evaluated to generate an evaluation result. An intensity of the laser beam is optimized in response to the evaluation result.

Abstract: Prevention of deletion of data in an unintended recording layer of an optical disc is ensured even when servo deviation occurs while controlling data reproduction. A light source outputs a light beam with light intensity according to a driving current on which a high frequency signal is superimposed. The light beam is collected on a recording layer of an optical disc. As triggered by detection of servo deviation during data reproduction, a light intensity controller adjusts a superimposed amount of the high frequency signal in the driving current to suit to a specific recording layer with the lowest reproduction tolerance in the optical disc and thereby controls the light intensity of the light beam output from the light source.

Abstract: In a dye-type optical recording medium, a write strategy for use in recording is determined based on recommended write strategy parameters recorded on an optical disk (160) and the characteristics of the optical recording device, and recording is carried out on the optical disk (160) according to the determined write strategy. In a medium of the phase change type, a power ratio and modulation degree for use in recording are determined from a recommended pulse width value in the recommended write strategy parameters recorded in the optical disk (160), the recommended power ratio value, the recommended recording power value, and the characteristics of the optical recording device, and recording is carried out on the optical disk (160) according to the power ratio value and modulation degree value thus determined.