Abstract: Disclosed herein is a laser driving apparatus, including: a driving unit adapted to current drive a laser device with a current value in accordance with a level of a signal supplied thereto; and an emission light waveform correction unit adapted to receive supply of a pulsed reference signal and generate, based on a correction timing pulse interlocked with a rising edge and/or a falling edge of a pulse, a correction signal having a level different from that of the reference signal and then supply the correction signal to the driving unit so that the shape of the emission light waveform of the laser device becomes close to that of a rectangular wave.

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 storage apparatus and a method for eliminating a write power transient thereof are provided. The method includes following steps. First, a target voltage level of a write voltage when next time the optical storage apparatus writes data is obtained. Then, a command value is updated by using the target voltage level according to a relationship between the command value and the write voltage. Next, the write voltage of the optical storage apparatus is pre-charged to the target voltage level according to the updated command value. Thereby, the write power transient of the optical storage apparatus can be eliminated.

Abstract: Amplitude and frequency of a high-frequency signal superposed on a reproduction laser beam are changed in accordance with a reproduction spot diameter on the surface of the recording layer upon discrimination of an optical disk in initial adjustment after insertion of the optical disk and change of a layer of a multi-layer optical disk. Further, the high-frequency signal is not superposed on the reproduction laser beam until end of the discrimination and change to a target layer upon discrimination of the optical disk and change of a layer of a multi-layer optical disk.

Abstract: An information recording medium having a disc shape and a recording layer configured to store information by light, the information being configured to be recorded on the recording layer with a mark and a space, wherein a channel clock period, represented by T, is provided for recording the mark on the recording layer. A mark corresponding to 2T or more can be recorded, and write parameter information is recorded on a particular area of the information recording medium. The parameter information includes a first peak power value used for a standard recording speed, and a second peak power value used for an increased recording speed which is a quadruple of the standard recording speed, the second peak power value being greater than the first peak power value.

Abstract: There is provided an optical recording method for directing a recording pulse train to an optical disc medium to form marks thereon and for recording information as information about the edge positions of said marks and the spaces between marks, the recording pulse train having been created by modulating laser light into plural power levels. The method includes: coding to-be-recorded data into coded data consisting of the combination of marks and spaces; classifying said marks within said coded data on the basis of the mark length and the preceding or succeeding space lengths of the marks; shifting the position of the second pulse edge counted from the end portion of the recording pulse train for forming said marks, depending on the result of said classification, to adjust said recording pulse train; and directing said recording pulse train to the optical disc medium to form said marks thereon.

Abstract: An input signal processing system is described. It comprises a first transconductance device having a first input, second input, and an output, wherein the first input is coupled to receive the input signal; a first resistor coupled to a first input of the first transconductance device, wherein the first resistor converts the input current signal to an input voltage signal; a first voltage-current converter coupled to the output, the second input, the resistor, and a low voltage supply, wherein the first voltage-current converter is operative for converting the input voltage signal to a input current signal; and a low pass filter having an input coupled to the voltage converter for filtering noise from the input current signal.

Abstract: The present invention relates to methods for on-line calibrating output power of an optical pick-up. A power adjusting circuit of the optical pick-up has an optical power regulator and an optical power detector. The on-line output power calibrating method includes the steps of: performing a recording pre-process; providing a focus offset value and/or a tilt offset value to the optical pick-up; providing a setting value, corresponding to power under test, to the optical power regulator; detecting laser power emitted from the optical pick-up using the optical power detector; comparing the laser power with the power under test to adjust the setting value of the optical power regulator corresponding to the power under test; and performing an optimum power calibration if the laser power emitted from the optical pick-up conforms to the power under test.

Abstract: The present invention contributes to getting a reproduction/recording operation done with stability on an information recording medium by utilizing an absorption edge shifting phenomenon. An apparatus 100 according to the present invention includes: a light source 20 for emitting a laser beam; a lens 6 for condensing the beam onto an information recording medium 21; and a photodetector 19 for detecting light reflected from the medium 21, of which a recording layer includes a material that absorbs the beam at an increasing absorptance as the absorption edge of a light absorption spectrum shifts, with a rise in temperature, toward a longer wavelength range as a result of a band-to-band transition of electrons.

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: An information recording medium, comprising N number (N is an integer fulfilling N?3) of information layers on which information is recordable, and allowing information to be recorded on each of the information layers and allowing information recorded on each of the information layers to be reproduced by being irradiated with laser light. The N number of information layers include an N'th information layer, an (N?1)th information layer, an (N?2)th information layer, . . . a second information layer and a first information layer sequentially located from a laser light incidence side. A reflectance of the N'th information layer is RN, and a reflectance of an M'th information layer (M refers to every integer fulfilling N>M?1) is RM.

Abstract: To ensure a favorable recording characteristic for a write-once recording medium for a bluish-purple laser, an optical information recording apparatus includes ways to write power to form recording marks, a space forming power to form spaces, pulse width of a cooling pulse and ways to record information onto the optical information recording medium according to the setting of the write power, the setting of the space forming power and the setting of the pulse width of the cooling pulse. At this time, the pulse width of the cooling pulse and a ratio whose numerator is the write power and whose denominator is the space forming power have a preferable region of the recording characteristic, and information is recorded onto the optical recording medium by using values in this range.

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: In order to ensure a favorable recording characteristic for a write-once recording medium whose recording layer is made of an organic dye having an absorption spectrum at a wavelength ?=405 nm, this optical information recording apparatus includes a unit to set a write power to form recording marks, a space forming power to form spaces and a pulse width of a cooling pulse, and a unit to record information onto the recording medium according to the setting. The pulse width of the cooling pulse and a ratio of the space recording power to the write power are determined from a favorable region in a plane whose one coordinate axis represents the ratio and whose other coordinate axis represents the pulse width of the cooling pulse.

Abstract: An optical disc apparatus for recording or reproducing on or from an optical disc, comprising a laser light source for emitting a laser beam; a drive portion for driving the laser light source; a detection portion for detecting the emission power of the laser beam; and means for focusing the laser beam onto the optical disc, wherein information is reproduced by a reproducing power varied according to a recording power to obtain reproducing signals having necessary quality while suppressing deterioration of the recording quality due to the reproducing power.

Abstract: An optical recording medium which includes three or more information layers and has a higher stack density of information layers than before in the direction of thickness while reducing crosstalk during reproduction, and a method for reading the optical recording medium are provided. The optical recording medium has a three-layer structure which includes a substrate, a first information layer, a first spacer layer, a second information layer, a second spacer layer, a third information layer, and a cover layer thinner than the substrate, with these layers being stacked in that order over the substrate, wherein the following Equation (I) is satisfied: (R2×R3×R2)/R1?0.0032??Equation (I) where R1 is the reflectivity of the first information layer, R2 is the reflectivity of the second information layer, and R3 is the reflectivity of the third information layer, and the first spacer layer and the second spacer layer are equal to each other in thickness.

Abstract: Provided are a method of controlling a recording operation in an optical disc drive to improve recording quality and an optical disc drive employing the method. The method includes setting recording power and parameters related to the generation of recording pulses by successively performing an optimum power controlling (OPC) process for adjusting recording power and an optimum write strategy (WST) tuning control (OWC) process for adjusting parameters related to the generation of recording pulses. The method also includes performing data recording based on the set recording power and the set parameters related to the generation of recording pulses.

Abstract: There is provided an optical recording method for directing a recording pulse train to an optical disc medium to form marks thereon and for recording information as information about the edge positions of said marks and the spaces between marks, the recording pulse train having been created by modulating laser light into plural power levels. The method includes: coding to-be-recorded data into coded data consisting of the combination of marks and spaces; classifying said marks within said coded data on the basis of the mark length and the preceding or succeeding space lengths of the marks; shifting the position of the second pulse edge counted from the end portion of the recording pulse train for forming said marks, depending on the result of said classification, to adjust said recording pulse train; and directing said recording pulse train to the optical disc medium to form said marks thereon.

Abstract: An optical disc recording method includes: determining that an optical disc to be recorded is an optical disc including a recording layer comprising organic dye; and controlling a laser such that space formation power Ps necessary for space formation is equal to or smaller than bias power Pbw. In a case wherein the relation of Ps<Pbw is satisfied, the relation between the asymmetry value, ? value, and main power Pw includes substantial linearity. Accordingly, control of the main power Pw can be performed with the asymmetry value and ? value as evaluation indexes, and accordingly, disturbance or the like can be readily handled.

Abstract: According to one embodiment, single-sided dual-layer recordable disc 100 may be used. Information recording is performed by forming mark and space portions on data area DA using modulated laser power. Pp denotes the maximum laser power or peak power for forming the mark portion, and Pb denotes the bias power for forming the space portion. Power ratio Pb/Pp is calculated for each of recording layers L0 and L1. Information is recorded on any of the recording layers L0 and L1 based on the result of calculation. Here, the calculated power ratio Pb/Pp changes among the recording layers L0 and L1, thereby optimizing the recording condition for a multi-layer recordable optical disc within relatively short time.

Abstract: Techniques are provided for controlling the reading of micro-holograms from a holographic disk based on a target data layer to be read in the disk. Reading a target data layer which is relatively deeper in the disk (e.g., farther from an optical head emitting a reading beam) may involve using a higher power reading beam to compensate for power attenuation of the returned reading beam. For example, a power adjustment module may be used to dynamically adjust a reading laser emitting the reading beam, based on the dynamically changing target data layer. By compensating for power attenuation in deeper target data layers, the variance of power in the returned reading beams may be decreased, possibly improving the bit error rate in micro-hologram reading techniques.

Abstract: In an optical disk recording apparatus, a monitor monitors a recording power of a laser light. A laser control circuit enables a laser diode to perform test recording while using the monitor to monitor the recording power of the laser light and while controlling a laser drive voltage, so that the monitored recording power reaches a given reference value during the test recording. A voltage measurement section measures the laser drive voltage when the recording power of the laser light reaches the reference value. A calculation section calculates an initial laser drive voltage from the reference value of the recording power and the measured laser drive voltage corresponding to the reference value. A main controller allows the laser control circuit to set the calculated initial laser drive voltage and to start the recording while supplying the laser control circuit with the target value so that an actual recording power of the laser light promptly reaches the target value during the course of the recording.

Abstract: A recording method suitable for high-density recording is provided to increase the reproduction quality. An optical information recording method is for recording information on an optical recording medium by irradiation of a write pulse of a laser beam to perform reproduction in a production system using a PRML detection scheme. The method includes recording a recording mark by a single write pulse, when the total length of the recording mark to be recorded and a space adjacent to the recording mark is less than a diameter of an effective reproduction spot, being 0.82×(?/NA), where ? is a wavelength of a reproduction laser beam and NA is a numerical aperture.

Abstract: A disc device for recording and/or reproducing information with respect to a disc having flexibility includes a head for writing and/or reading, the head being disposed below the disc; a disc rotating section which rotates the disc; and a head retracting section which retracts the head to a retracted position where contact with the disc is avoidable, based on a judgment that power supply to the disc device is cut off.

Abstract: An optical disc recording method of determining a disc address when write and read operations are performed for an optical disc during recording power calibration in an optical disc recording apparatus having at least two optical head units including first and second optical head units is disclosed. The method includes: determining a first recording power calibration start address, which is an address at which the first optical head unit starts calibration of the recording power, from a power calibration area provided in advance as an area used to calibrate the recording power; and determining an address obtained by adding a range of the power calibration area used to calibrate the recording power to the first recording power calibration start address as a second recording power calibration start address, which is an address at which the second optical head unit starts calibration of the recording power.

Abstract: The invention relates to recording methods for recording information on a dual layer recordable disk, and to corresponding recording devices. In one such method and recording device the OPC-area is variably located on a layer of the disk. In a preferred embodiment the OPC-area is located relative close to the radius where the data stream switches from the first layer to the second layer. This reduced additional time required for jumping to a fixed OPC-area. Furthermore, in another such method and device the information to be recorded is equally divided over both layers of the dual layer disc. This avoids additional time required for finalization.

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: The invention provides an optical disc apparatus which prevents that a laser beam whose power is set at a read power level causes erroneous data recording or deletion. The optical disc apparatus includes an emission controller which controls an amount of an electrical current that a current supply portion supplies to a laser diode in order to control a level of emission power at which the laser diode emits the laser beam. The emission controller has a function to set levels of the emission power at the following transition processings: a transition processing after a read processing and before a write processing, a transition processing after a write processing and before a read processing, a transition processing between two read processings for respective areas, and a transition processing between two write processings for respective areas.

Abstract: When a laser light focal point, driven by an objective lens, passes through each of a plurality of recording layers of an optical disc, data recorded on the recording layers through which the focal point passes may be deteriorated due to a difference in optical sensitivity for each recording layer or the like. In a focal point position movement in which switching of recording layers is made by a focus error signal, when the focal point position moves from a recording layer on which a laser light is focused to another recording layer which is not adjacent, light intensity or light density at the focal point is reduced in accordance with the recording layer to be passed through, thus deterioration of the data on the optical disc being prevented.

Abstract: A method for tuning a plurality of write strategy parameters of an optical storage device includes detecting a plurality of patterns. Each pattern corresponds to a pit or a land on a phase-changed type optical storage medium accessed by the optical storage device. The method further includes performing calculations corresponding to a plurality of data types and generating a plurality of data-to-clock edge deviations respectively corresponding to the data types. Each pattern belongs to a data type. The data-to-clock edge deviations are utilized for tuning the write strategy parameters corresponding to the data types respectively.

Abstract: An optical disc apparatus includes a light source for emitting laser light, a light source drive unit for driving said light source, an optical element for splitting the laser light into a plurality of light fluxes, an optical element drive unit for controlling the optical element, an element for focusing the laser light onto the optical disc, and a detection unit for detecting the laser light reflected by the optical disc. Reproduction of the optical disc is performed by switching effectiveness and ineffectiveness of a function of splitting the light flux of the optical element, and adjustment of an outgoing laser power is performed.

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: 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: 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/reproducing device includes a laser and a laser drive carried by a pickup having a drive for movement. A control controls the drives to irradiate the recording medium with laser pulse sequences forming recording marks having recording mark lengths between a predetermined and maximum lengths, a top section, a last section including a cooling period, and an intermediate period. Heat of mark front edges is controlled by recording parameters for top sections that are classified according to recording mark lengths and recording parameters of the first through the maximum recording mark lengths are classified into a same group. Heat of mark rear edges is controlled by cooling start positions for cooling periods classified according to recording mark lengths. Cooling start positions for a second predetermined mark length through the maximum mark length are classified into a same group. The second mark length is longer than the first mark length.

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: By referring to a table of reproducing conditions and medium specific parameters, stored in an optical disc or optical disc apparatus and/or generated by the optical disc apparatus, the medium specific parameters to be used for performing reproducing power adjustment are changed in accordance with the reproducing condition to execute reproducing power adjustment.

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: An optical disc recording medium is irradiated with laser light having a predetermined laser power to deform an irradiated portion of a substrate into a protruding portion. Since the substrate is deformed so as to have protruding portions, a reflecting layer arranged on the substrate is also deformed so as to have protruding portions. For a pit, the deformed state of a protruding portion allows to obtain a reproduced signal level equivalent to that in each land. For a land, the deformed state of a protruding portion allows to obtain a reproduced signal level equivalent to that in each pit. Since the deformed state of each protruding portion can be controlled on the basis of the power of the laser light for irradiation, pit-to-land deformation and land-to-pit deformation can be performed by setting the laser power. Thus, recorded data can be rewritten on the optical disc recording medium recorded with the data using a combination of pits and lands formed in the substrate.

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 parameter setting device including a trial recording parameter setting section and a reproduced signal quality judging section. The reproduced signal quality judging section judges whether or not a reproduced signal obtained by reproduction of the trial recording carried out in accordance with the trial recording parameter satisfies a predetermined reproduced signal quality. If no, the recording parameters of the predetermined recording mark length or longer are further classified into detailed groups and trial recording is carried out again. If the reproduced signal satisfies the predetermined reproduced signal quality, the reproduced signal quality judging section sets the trial recording parameters as a recording parameter. This makes it possible to form a recording mark capable of surely providing a good reproduced signal quality while the number of recording parameters to be used is reduced.

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: 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.