Abstract: An optical information read/write apparatus according to the present invention includes: a light source 1 that emits a laser beam to access an information storage medium optically; a laser driver 51a for supplying drive current to a semiconductor laser as the light source 1; an RE superimposed current generator 51c for adding RE superimposed current to the drive current; a temperature sensor 35 for detecting a temperature around the light source 1; and a control section for switching the values of the RE superimposed current according to the temperature detected.

Abstract: An optical disc apparatus for recording information on a rewritable optical disc having a power calibration area (PCA) moves an optical pickup for optimum recording power calibration (OPC) from an innermost end to outward of the PCA, and stores an address where RF signal is first detected. If the stored address coincides with an address at the innermost end of the PCA, or if a usable area between the two addresses is smaller than to enable one-time OPC, the apparatus obtains an optimum recording power by overwriting on a used area at or near the innermost end of the PCA, and performs DC erase using the obtained optimum recording power. This enables DC erase and restoration of the PCA back to a usable area even if the PCA has no usable area at its innermost end, and even if it is difficult to detect a usable area in the PCA.

Abstract: Within an optical disk recording/reproducing apparatus, equipped with a test writing method during the recording operation, for improving accuracy on calculating the most-suitable power and recording quality, thereby recording data through irradiation of a laser beam of a predetermined power onto a optical disk, defining test writing areas on an inner periphery side and an outer periphery side and an area recordable with data between those inner periphery side and outer periphery side, or reproducing data recorded thereon from a reflection light thereupon, wherein a controller circuit 9 executes a test writing process, with selecting a test writing area on a periphery side being large in a ratio of difference, upon basis of ratios of the differences between powers on an inner periphery and an outer periphery of said disk, which are set up at present, and control data on the inner periphery and the outer periphery, which are recorded on said optical disk loaded therein, when executing the test writing process

Abstract: A method for controlling a specific output power level emitted from a laser diode (LD) in an optical pick-up head unit (OPU) is disclosed. The LD is configured to provide a plurality of output power levels for accessing/recording an optical disc. The method includes: determining a specific power control value according to a first output power level, a second output power level, a first power control value of the first output power level, and the specific output power level, wherein the first output power level is less than the specific output power level and greater than the second output power level; and driving the LD to emit the specific output power level according to the specific power control value, the first power control value, and a second power control value of the second output power level.

Abstract: Test signals are sequentially generated. A laser beam inclusive of the generated test signals is applied to a preset test recording area in a disc-shaped recording medium to record the generated test signals thereon. A recording power of the applied laser beam is changed stepwise from a lowest level to a highest level through different intermediate levels. The lowest level, the highest level, and the intermediate levels the recording power of the applied laser beam takes are assigned to the test signals respectively. The recorded test signals are reproduced from the preset test recording area in the disc-shaped recording medium. An optimum value of a laser-beam recording power is decided on the basis of the reproduced test signals and at least one of the lowest level, the highest level, and the intermediate levels.

Abstract: A method and apparatus to record data on an optical recording medium include generating a recording waveform having an erase pattern comprising a multi-pulse having a high level which is higher than an erase power level and a low level which is lower than the erase power level. A power level of a leading one of the multi-pulse of the erase pattern and a power level between an end of the erase pattern and a start point of a leading pulse of a recording pattern are controlled to be the low level and the high level, respectively, the high level and the high level, respectively, the high level and the low level, respectively, or the low level and the low level, respectively.

Abstract: An apparatus and method for controlling a recording signal are provided. The apparatus may include a light generator generating light used to write information to an optical disk, a light amount compensator setting a voltage level of the recording signal as a second level when the write operation is performed or stopped, and a light amount controller supplying energy to the light generator based on the second level of the recording signal until the voltage level of the recording signal reaches a first level when a rewrite operation is started and controlling the light generated by the light generator to be constant after the voltage level of the recording signal reaches the first level.

Abstract: An optical information recording and reproducing apparatus comprises an optical disk having a reflection layer, an optical information recording layer, a super resolution layer and a protection layer on the recording surface of a substrate, a laser emission control unit for emitting the laser light to record and reproduce the optical information and changing the pulse-like emission pattern, a pickup for radiating by focusing the laser light and receiving the reflected light, a spindle and a spindle motor for supporting and rotationally driving the optical disk, and a reproduction signal processing unit for arithmetically processing the received signal.

Abstract: Recording information is disclosed in which an information recording medium is irradiated with a recording energy beam that is power-modulated into at least a record power level and a record-ready power level lower than the record power level. The information is recorded on the recording medium in the form of length and interval of a mark portion. When forming a mark portion of a predetermined length, the radiation energy of the energy beam is increased as compared with when forming a mark portion of a different length before or after the first pulse of an energy beam pulse train including at least a pulse for forming the mark portion.

Abstract: A method for recording information on an optical recording medium is provided so that it is satisfied that 0.16?(Lv×Tcool)/(?/NA)?0.30 and 0.06?(Lv×Ttop)/(?/NA)?0.14, where ? is a write wavelength of a laser beam used to irradiate the recording layer of a phase-change optical recording medium, NA is a numerical aperture of an objective lens used for irradiation with the laser beam, Lv is a relative speed between the objective lens and the optical recording medium, Tcool is a pulse time of a cooling pulse inserted immediately following a leading write pulse, and Ttop is a leading write pulse time. The method allows for forming a record mark with a good shape and prevents fluctuations at the front edge of the record mark, which would be otherwise caused by the recrystallization of the recording film being held at a high temperature.

Abstract: The present invention relates to an optical holographic device and a corresponding method for reading out a data page recorded in a holographic recording medium (106). In order to improve the bit error rate a reconstruction means (115) provided for reconstructing a dark and a light image from a separate checkerboard page comprising a pattern of dark and light pixels or from the detected imaged data page, and an image correction means (116) is provided for correcting said detected imaged data page by gain compensation using said reconstructed dark and light images.

Abstract: A power control device of multi base powers is provided for an optical read/write module of an optical disk drive. The optical read/write module generates a power feedback signal and a temperature signal. The power control device includes a base power selecting module, a current compensating module, a current computing module and a current integrating module. The base power selecting module selects one of a first base power signal and a second base power signal to output a base power signal. The current compensating module generates an operating current compensating signal and a threshold compensating signal according to the power feedback signal, the temperature signal, the base power signal and a function relationship between the temperature signal and the threshold current of the optical read/write module.

Abstract: A warpage angle measurement apparatus and a warpage angle measurement method are provided that can measure an angle of warpage of an optical disc and a cartridge for the optical disc caused by a rapid environmental change such as a temperature change or a humidity change in a short time. The warpage angle measurement apparatus 10 includes: a constant temperature chamber 22 for accommodating an optical recording medium 20 formed by mounting the optical disc 16 as an object to be measured in the cartridge 18 and for adjusting a surrounding of the optical recording medium 20 to have a predetermined environmental condition; a laser oscillator 24 for causing laser oscillation to emit laser light to the optical disc 16; and a light-receiving unit 26 for receiving the laser light reflected from the optical disc 16 and detecting a relative angle of an optical path L2 of the reflected laser light with respect to an optical path L1 of the emitted laser light.

Abstract: A method and apparatus for writing data to a rewritable ultra-speed disc using an optimum pulse at a write speed of the disc, based on Absolute Time in Pre-groove (ATIP) information. The method includes: reading a disc code from the disc; determining a write speed of the disc from the read disc code; and writing data to the disc. The writing is at the determined write speed and according to a write strategy when the write strategy for the lead-in area is determined to be present, and is according on a default write strategy when the write strategy for the lead-in area is determined not to be present.

Abstract: An optical head that is restrained from becoming larger, even if it is used for an optical-information recording medium that includes a plurality of information recording layers. In this optical head, a collimating lens is formed by a concave lens disposed on the side of a light source and a convex lens disposed on the side of an objective lens. A collimating-lens actuator moves the convex lens in a direction where a spherical aberration is cancelled which is generated according to the thickness of a light transmission layer up to an information recording layer of the optical-information recording medium. An aperture stop is provided on the side of the collimating lens with respect to the objective lens, and the aperture stop is located near the focal position of the convex lens on the side of the objective lens.

Abstract: The present invention proposes a method of controlling the laser power of a semiconductor laser that, in this method of controlling the laser power of a semiconductor laser by applying a power source voltage to between the collector and emitter of an output transistor and a serial circuit of the output transistor and a semiconductor laser, enables decreasing the power consumption of the output transistor. The present invention is arranged to apply a variable power source voltage Vcc to a serial circuit of an output transistor (Qb) and a semiconductor laser (SL) and thereby control the variable power source voltage Vcc such that a difference between the variable power source voltage Vcc and the peak hold voltage of an operating voltage of the semiconductor laser (SL) becomes substantially constant.

Abstract: A threshold current modifying device is provided for an optical pickup head. The optical pickup head initially generates an output power when an operating current is larger than a threshold current of the optical pickup head, and the threshold current is related to a temperature of the optical pickup head in a functional relationship. The threshold current modifying device includes a threshold current calculating module and a power control module. The threshold current calculating module receives a temperature signal from the optical pickup head at a first temperature to output a threshold current signal according to the temperature signal and the functional relationship. The power control module receives the threshold current signal to adjust the operating current.

Abstract: An optical information apparatus includes a laser which emits a light beam, an objective lens and the like which converge a light beam emitted from the laser on an optical recording medium, spherical aberration correction instrument which is arranged on an optical axis of the light beam which links the laser and the objective lens, and corrects a spherical aberration generated on the optical recording medium. Correction is performed so that outgoing power of the laser changes according to a correction amount by the spherical aberration correction instrument.

Abstract: The present invention relates to apparatuses and processes for recording dye-based recordable DVD media in higher quality at higher linear recording velocity, and provides an apparatus for recording a dye-based recordable DVD medium comprising a shortest mark recording unit, a second mark recording unit, and a cooling pulse irradiating unit, wherein the dye-based recordable DVD medium comprises a substrate and a recording layer formed on the substrate, the substrate comprises a guide groove to which wobble is formed, and the recording layer comprises at least an organic dye, the shortest mark recording unit is configured to record each of the shortest marks by use of one pulse beam of which the rear edge is more energized than the front edge, the second mark recording unit is configured to record each of the marks other than the shortest marks by use of one pulse beam of which the two sites of front and rear edges are energized, the cooling pulse irradiating unit is configured to irradiate cooling pulse laser

Abstract: A recording/reproduction apparatus, comprising a first recording section for recording test information onto a medium using at least one recording power, a reproduction section for reproducing at least one test signal indicating the test information from the medium, and a second recording section for recording information onto the medium using one of the at least one recording power. The reproduction section comprises a decoding section for performing maximum likelihood decoding of the at least one test signal and generating at least one binary signal indicating a result of the maximum likelihood decoding, a calculation section for calculating a reliability of the result of the maximum likelihood decoding based on the at least one test signal and the at least one binary signal, and an adjustment section for adjusting a recording power for recording the information onto the medium to the one recording power based on the reliability.

Abstract: To make the output voltage of a laser power monitor circuit (12) equal to a predetermined value at a predetermined laser power, adjustment is performed by changing an external variable resistance for output voltage adjustment. To achieve this, adjustment is performed by changing the variable resistance so that the difference between a high level output pulse of the laser power monitor circuit (12) obtained when an LD (11) is turned off and a low level output pulse obtained when the LD (11) is turned on is made equal to a target adjusted voltage. This prevents the offset of the laser power monitor circuit (12) from affecting a monitor output voltage, allowing an optical pickup to perform, for example, recording and reproducing with higher accuracy.

Abstract: A multilayer optical recording medium includes three or more recording layers formed in a thickness direction. Trial writing areas provided in the respective recording layers to adjust the power of recording laser are formed not to overlap at a position in a planar direction in adjacent ones of the recording layers. Further, the trial writing areas are formed to have an overlapping portion at a position in the planar direction in one of the recording layers and at least another one of the recording layers not adjacent to the one of the recording layers.

Abstract: A recording condition setting method includes the steps of: a) obtaining identification information from an information recording medium; b) searching through a table including history information indicative of temperature information detected in the vicinity of a light source and corresponding optimum recording power; c) extracting history information corresponding to the identification information; d) detecting temperature information detected in the vicinity of the light source; e) acquiring an optimum recording power by referring to the temperature information detected in step d) and the history information extracted in step c); and f) setting the optimum recording power acquired in step e) as a recording condition.

Abstract: An optical disk device includes a recording power acquiring unit which acquires recording power, a recording unit which records data on an optical disk set in a device body by irradiating laser light of the recording power onto the optical disk, and a laser power control unit which controls power of the laser light. Preferably, the recording power is suited to record data on the optical disk, and the laser power control unit gradually decreases the power of the laser light irradiated in a linking region from the recording power based on a first prescribed condition when recording of data by the recording unit is ended and gradually increases the power of the laser light irradiated in the linking region to the recording power based on a second prescribed condition when the recording of data by the recording unit is started.

Abstract: A power control device of single base power is provided for an optical read/write module of an optical disk drive. The optical read/write module generates a power feedback signal and a temperature signal. The power control device includes a current compensating module, a current computing module and a current integrating module. The current compensating module generates an operating current compensating signal and a threshold compensating signal according to the power feedback signal, the temperature signal, a base power signal and a function relationship between the temperature signal and the threshold current of the optical read/write module. The current computing module receives the operating current compensating signal to compute a first operating current signal and a second operating current signal based on the operating current compensating signal according to the base power signal and a reference power signal.

Abstract: A front photo detector (FPD) of an optical pick-up for an optical recording and playing apparatus having no gain selection switch, a simplified configuration, an improved prevention of an abnormal operation due to an error in gain selection, and improved reliability. The front photo detector includes a photo diode unit, a current-voltage amplifying circuit, and a voltage amplifying unit. The photo diode unit outputs current proportional to the power of the light emitted from one of a plurality of laser diodes. The current-voltage amplifying circuit converts the current output from the photo diode unit into a voltage. The voltage amplifying circuit amplifies the voltage output from the current-voltage amplifying circuit by a predetermined gain.

Abstract: A method of producing a data carrier with a marking is disclosed. The data carrier includes a laser-markable portion and a beam-modifying portion adjacent the laser-markable portion. The beam-modifying portion has a beam modifying property. The method includes irradiating a laser beam through the beam-modifying portion to allow the beam modifying property thereof to modify at least one beam property to produce a resultant laser beam. This resultant laser beam creates a marking with a visual impression corresponding to the resultant laser beam at the laser-markable portion. The method further includes modifying the beam modifying property of at least a part of the beam-modifying portion through which the laser beam is irradiated for creating the marking so that the exact same resultant beam is difficult to be obtained thereat. A data carrier thereby produced is also disclosed.

Abstract: A calibration method for improving stability of write control signal during writing can be applied in a CD recorder. The CD recorder has a pickup device having a laser diode, and a write control device for outputting a write control signal. A first relationship curve showing the relationship between the write control signal and a light-emitting power generated by the laser diode is obtained by switching the pickup device into a de-focus state and switching the write control device into a close-loop mode. A second relationship curve showing the relationship between a gain of the write control device and the write control signal is obtained by switching the write control device into a long-term open mode. When a specific light-emitting power is adapted to write, a specific write control signal and a specific gain corresponding to the specific light-emitting power is obtained according to the first and second relationship curves.

Abstract: A method for calibrating a recording condition in an information recording unit includes: heating a recorded data pattern recorded on the information recording medium; reproducing the recorded data pattern after the heating, to measure a reproduced-signal quality; and determining a recording condition based on the measured reproduced-signal quality.

Abstract: An optical storage medium can be provided by which illegal usage of the optical storage medium involving an infringement on the copyright can be prevented effectively without impairment of the functions for reproducing physical format information and optical storage medium manufacturing information. The optical storage medium includes a main information region in which encrypted data information is recorded as a pit row that is capable of being read out by means of light and a control data region. In the control data region, key information for decoding the encryption of the data information, the physical format information and the optical storage medium manufacturing information are recorded by wobbling a groove.

Abstract: A rewritable optical recording medium includes a substrate and a phase-change type recording layer. A portion in a crystalline state corresponds to an unrecorded or erased state, and a portion in an amorphous state correspond to a recorded state, to record EFM modulated information by forming amorphous marks by irradiating the recording layer with a recording laser beam, and the recording is carried out by irradiating a recording laser beam having a wavelength of about 780 nm through an optical system having a numerical aperture NA of 0.5 or 0.55, at 24-times velocity or 32-times velocity of the reference velocity.

Abstract: An information recording apparatus for recording information with less waveform deformation with an adequate modulation degree and with a high asymmetry, an information recording method, and an information recording program. An information recording apparatus in which a laser beam is applied to a recording medium and a recording mark corresponding to a recording signal is formed includes a light source for emitting a laser beam and signal generating means for generating a recording pulse signal for driving the light source according to the recording signal. The recording pulse signal includes a mark period during which a recording mark is formed and a space period during which no recording mark is formed. During the mark period corresponding to a long mark, the level of the recording pulse signal corresponds to a recording power with which the reproduction compatibility is ensured and the waveform distortion is at or below a predetermined value.

Abstract: In a recording method or apparatus, in order to set an optimal recording condition by a minimal number of times of testing, test recording is carried out while changing power and pulse width of recording pulses in a stepwise manner. Conditions for the test recording are concentrated in a region of a matrix defined by power×pulse width.

Abstract: The optical head device includes a semiconductor laser for emitting a laser beam having an elliptical beam shape; a collimator lens for collimating the laser beam emitted from the semiconductor laser; a reflector including pair of belt-like pieces one of the surfaces of which is used as a reflecting face formed in a curved face having a curvature along their longitudinal direction, the pair of belt-like pieces being formed to be arranged in a major axis direction of an elliptical beam flux to sandwich the optical axis of the laser beam, and an optical sensor equipped with a condenser lens for detecting the strength of the beam reflected from the pair of belt-like pieces of the reflector.

Abstract: An apparatus comprising a first circuit, a second circuit and a third circuit. The first circuit may be configured to (i) generate a read power signal and (ii) control power of a laser beam emitted from an optical pick-up circuit during a read process. The second circuit may be configured to (i) generate a first write power signal and (ii) control one or more power levels of the laser beam during a write process in response to a second write power signal. The third circuit may be configured to generate the second write power signal and a third write power signal in response to a target write signal.

Abstract: The invention relates to write strategy modification, and in particular, to dynamic write strategy modification. A dynamic write strategy modification method comprises: writing a plurality of data on to an optical disk according to a writing strategy with at least three parameters; measuring at least two quality indices of the data wrote on the optical disk; storing a result comprising the parameters and the corresponding quality indices; judging whether a terminate condition is achieved; if no, changing the parameters and repeating the above steps; if yes, analyzing the stored results and outputting an optimal writing strategy with at least three optimal parameters.

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.

Abstract: An optical disk drive includes drive current generation unit for supplying a mark forming semiconductor laser drive current and a space forming semiconductor laser drive current; first high-frequency superimposition unit for superimposing a high-frequency component on the space forming semiconductor laser drive current; and high-frequency superimposition control unit for controlling the first high-frequency superimposition unit to stop the superimposition of the high-frequency component for a predetermined duration prior to a timing at which to switch from the space forming semiconductor laser drive current to the mark forming semiconductor laser drive current, eliminating positional variations on the disk of the mark leading and trailing edges due to the high frequency superimposition.

Abstract: A method is designed for determining optimum power values of optical beams emitted from a plurality of optical pickups provided in an optical disk recording apparatus. In the method, a first step is performed for performing test recording of data by use of the plurality of the optical pickups, respectively, such that each optical pickup is operated to irradiate an optical beam onto the optical disk for recording data on a test area of the optical disk. A second step is performed for reproducing respective data recorded in the test area by the respective optical pickups, by use of a predetermined one of the plurality of the optical pickups. A third step is performed for judging ? values from the respective data reproduced from the test area. A fourth step is performed for determining, from the judged ? values, the optimum power values of the optical beams for the respective optical pickups.

Abstract: According to one embodiment, in one embodiment of the invention, a laser drive circuit is provided with a first current source, a second drive current source, and a third current source. The control section selectively obtains a plurality of laser light use mode of controlling the from first to third current sources to use pulse laser light accompanying relaxation oscillation, and a complex laser light use mode of using laser light where laser pulses are combined, whose starting end has an abrupt impulse change portion caused by relaxation oscillation and whose intermediate section is a flat portion with a fixed intensity.

Abstract: In an optical disk apparatus, transmittance and reflectance of a polarization beam splitter 13 to the S polarization and the P polarization of laser beams are adjusted so that a first polarization component level ratio in the laser beam received by a light receiver for reproducing signal 17 from a laser diode 11 via the polarization beam splitter 13, and a second polarization component level ratio in the laser beam received by a light receiver for monitoring light source 18 from the laser diode 11 via the polarization beam splitter 13 become equal or the difference between the first and the second polarization component level ratios becomes within a predetermined permissible range.

Abstract: A power control method is provided for an optical disk drive. The optical disk drive has an optical read/write module for accessing an optical storage media. The power control method includes the following steps: measuring the temperature of the optical read/write module; predicting a threshold current of the optical read/write module according to the temperature; determine the accessing mode of the optical storage media; measuring the output power of the optical read/write module; computing a first current required for the optical read/write module according to the output power of the optical read/write module and a base power in the accessing mode; compensating the computed first current according to the predicted threshold current; and driving the optical read/write module according to the first current.

Abstract: A writing current circuit (42) supplies a controlled electrical current to a laser diode (34) for recording data swiftly onto a DVD (16). A plurality of thermometer code registers (52) respectively store numerical values. A current control register (58) receives a numerical value from one of the thermometer code registers (52). Serial data specifies a sequence in which individual thermometer code registers (52) supply values to the current control register (58) thereby causing the writing current circuit (42) to supply a particular electrical current waveform to the laser diode (34). A plurality of current sources (62) respectively receive a single output signal from the current control register (52) which activates or deactivates individual current sources (62) for supplying a particular quantity of current to the laser diode (34).

Abstract: An optical disk drive includes drive current generation unit for supplying a mark forming semiconductor laser drive current and a space forming semiconductor laser drive current; first high-frequency superimposition unit for superimposing a high-frequency component on the space forming semiconductor laser drive current; and high-frequency superimposition control unit for controlling the first high-frequency superimposition unit to stop the superimposition of the high-frequency component for a predetermined duration prior to a timing at which to switch from the space forming semiconductor laser drive current to the mark forming semiconductor laser drive current, eliminating positional variations on the disk of the mark leading and trailing edges due to the high frequency superimposition.

Abstract: An optical disk drive includes drive current generation unit for supplying a mark forming semiconductor laser drive current and a space forming semiconductor laser drive current; first high-frequency superimposition unit for superimposing a high-frequency component on the space forming semiconductor laser drive current; and high-frequency superimposition control unit for controlling the first high-frequency superimposition unit to stop the superimposition of the high-frequency component for a predetermined duration prior to a timing at which to switch from the space forming semiconductor laser drive current to the mark forming semiconductor laser drive current, eliminating positional variations on the disk of the mark leading and trailing edges due to the high frequency superimposition.

Abstract: A light detector includes a light-receiving device that receives a light beam applied from a light source irradiating an optical recording medium with the light beam and that generates detection signals, and a power monitor circuit section that generates a power monitor signal for monitoring output power of the light source in accordance with the detection signals. The device includes split light-receiving elements. The detection signals are output from the split light-receiving elements as split detection signals. The section includes an amplifying circuit generating the power monitor signal and outputting the power monitor signal as differential signals, a fixed resistor determining a gain of the amplifying circuit, and a position-detecting signal output circuit generating position-detecting signals in accordance with the split detection signals. At least the light-receiving device, the amplifying circuit, and the fixed resistor are integrated on an identical semiconductor substrate.

Abstract: Each of control powers of a first definition group that correspond to a pulse train used to form a recording mark, and a plurality of levels of a second definition group that includes each of the control powers of the first definition group in accordance with the conditions of a recording medium 3 are set. A plurality of control powers are selected from the first definition group included in the selected level of the second definition group. When the laser is driven with the corresponding drive values, a monitor 4 obtains an emission power detection value. The emission power detection value is stored for each level of the second definition group, and an occurrence is counted for each level of the second definition group in a period during which the emission power detection value is obtained.

Abstract: In order to set optimum laser power for a disk smoothly and appropriately with a small number of times of test writing, an integrated value Sn is obtained from each kind of laser power Pwn set for the test writing and the modulation factor m(Pwn) of a reflection light intensity obtained through the test writing with the laser power Pwn using an expression “Sn=m(Pwn)×Pwn2”, laser power Pwth is obtained at which the modulation factor m(Pwn) becomes zero when relational characteristics of the integrated value Sn and the laser power Pwn are linearly approximated, and optimum laser power Pw is set based on the laser power Pwth. Here, the optimum laser power Pw is obtained from the target ? value of the disk using an expression “Pw=Pwth×{1+1/(?+1)}”. The target ? value is obtained from an ADIP of the disk.

Abstract: A method and an apparatus for driving an optical recording medium for recording and/or reproducing various information for the optical recording medium, in which the output power ratio of the light source may be reduced for recording and reproduction, for optical recording media of different sorts, or for respective recording surfaces of a multilayered optical recording medium, so that optimum characteristics may be realized even with use of an easy-to-fabricate light source or a light source with a smaller light output rating.

Abstract: A laser drive device, a laser light emitting device and a laser driving method capable of preventing deterioration or failure of a laser element due to returned lights by defining a control limitation value taking into account an affection of the returned lights to the laser element by calculating a control limitation value of an output or current of the laser element based on first laser characteristic information on transmittance or reflectance of an output end face of the laser element, second laser characteristic information on a rated output value, or a rated current value and an oscillation threshold current value and third laser characteristic information on a returned light rate to the output end face of the laser element, so that a control limitation value taking into account an affection of the returned light is determined; then, by comparing said calculated control limitation value with an input control value; and driving the laser element in accordance with the control value when the control value