Abstract: Method and device for generating a stable power control signal in a CD recorder. The power control signal for controlling a laser diode may be a read level, an erase level and a write level. A pickup device outputs a feedback control signal to a read control circuit, and a read power control voltage is thus obtained. Then, the read power control voltage is inputted to a write control circuit, which generates first and second write power control voltages. The read level equals a reference voltage added by the read power control voltage, the erase level equals the read level added by the first write power control voltage, and the write level equals the erase level added by the second write power control voltage, so the read power control voltage and thus the read, erase and write levels are automatically and dynamically adjusted as the feedback control signal varies.

Abstract: A signal detection sections detect the light intensity modulated by the phase pits as ROM signals from the return lights of an optical storage medium that has phase pits and a recording layer to simultaneously regenerate data in the ROM and RAM, and detect the RAM signals where the return lights were modulated by the recording film. A feedback circuit reduces the cross-talk of the phase pits of the RAM signals of the recording film by feeding back the ROM signals to the laser drive current of the laser element, and a circuit for adjusting the feedback circuit so as to present a constant cross-talk suppression effect regardless the temperature change of the laser element. Since the feedback gain is changed by changing the laser temperature, an RF feedback gain, with which MO signals are not deteriorated by the change of the laser temperature, can be set.

Abstract: A method of and apparatus for recording data on an optical recording medium form a mark or a space by using a recording waveform having an erase pattern containing a multi-pulse. The method and the apparatus prevent distortion of the mark or the space and improve a mark shape such that a recording/reproducing characteristic of the optical recording medium is improved.

Abstract: In a detection element for the current which flows from a power source to a disk apparatus internal circuit, a plurality of resistors are incorporated such that the detection resistance for consumption current can be selected. Based on apparatus identification information from an apparatus identification unit 31 such as a current identification signal outputting circuit or an apparatus identification structure provided in a disk apparatus unit, the detection element switching circuit switches the detection resistance value of the detection element. A voltage detection circuit detects the potential difference between both terminals of the detection element. When a current control circuit detects an excessive current based on the potential difference, the current control circuit turns off a transistor (FET).

Abstract: A laser power controller includes a loop control section to control a laser light output level of an optical head that applies laser light onto a disk for recording data to be a prescribed value, a DAC control section to hold as a previous level a laser control level preceding switching of a laser output level upon track change between a groove track and a land track during recording, and an analog SW to select the DAC control section to control the laser light output level by the previous level for a certain time period from the track change and to select the loop control section after the certain time period.

Abstract: A method, apparatus, and medium for erasing information recorded on a rewritable recording medium. The method includes: searching for test result information on a recording power recorded on a recording management area disposed on the recording medium; if corresponding test result information is found, reading in the test result information; and by using a recording power determined according to the read test result, recording a unique pattern on at least part of a user data area of the recording medium where predetermined information is recorded. According to the method, the writing characteristic can be greatly improved.

Abstract: It is an object of the present invention to provide an information recording and reproducing technique capable of improving the reliability of information recorded on a recording medium. A recording condition comprising amplitude information and the ratio of the amplitude to the recording power is previously recorded on the recording medium. Using this previously recorded information, information is recorded and then immediately reproduced to calculate the optimum recording power from the amplitude information obtained from the reproduced signal. By adapting the recording condition accordingly, it is possible to secure reliability of information in performance.

Abstract: A semiconductor laser drive circuit of the present invention reduces the number of wires, solves the out-of-timing problem of pulses due to differences in wire length, and emit short light pulses at a high transfer rate. A common emitter circuit (18) converts a voltage signal (J1) input at an input port (18a) into a current signal and, when reading information, adds the current signal to a signal output from a high-frequency oscillator circuit (20). High frequency components of the current signal converted from the voltage signal (J1) within a bandwidth of a transistor (Q6) are boosted. Degradation of the output signal of the high-frequency oscillator circuit (20) is kept at a minimum by a common base circuit including the transistor (Q6). A current switch circuit (16) cuts off or lets through the output current of a current mirror circuit (12).

Abstract: A method of and apparatus for recording data on an optical recording medium form a mark or a space by using a recording waveform having an erase pattern containing a multi-pulse. The method and the apparatus prevent distortion of the mark or the space and improve a mark shape such that a recording/reproducing characteristic of the optical recording medium is improved.

Abstract: Prior to a main record, a trial write of data in an optical disc is performed in accordance with the characteristics between a record velocity and an optimum record power (Steps S2 to S4). The quality of a signal reproduced from the trial-written data is measured (Step S5). It is judged from the measured quality of the reproduced signal whether the predetermined velocity is a recordable velocity satisfying the characteristics between the record velocity and the optimum record power (Step 5). The main record is executed in accordance with the judgment result.

Abstract: In order to improve the frequency characteristic of a laser power monitor device and the precision of laser power control when low-speed recording is performed, there is provided a laser power monitor device for an optical recording and/or reproducing apparatus, the laser power monitor device including a photo diode unit to receive part of a light emitted from a laser diode and output a current proportional to optical power, and a monitor circuit to receive the current output from the photo diode unit, convert the received current into a voltage, and outputs the voltage to an automatic laser power control circuit, and the photo diode unit includes a plurality of photo diodes connected to the monitor circuit to supply current to the monitor circuit.

Abstract: An optical disc apparatus having a construction that lowers a peak value of a laser beam applied to an optical disc and controls a current supplied to the laser. Provisions are made to prevent recorded marks on the optical disc from degrading by utilizing the laser beam radiated onto the optical disc. Provisions are also made to minimize gradual deterioration of the laser itself that would otherwise be caused by the emission of laser beam, to minimize unwanted radio waves that would otherwise be produced from the optical disc apparatus by the emission of laser beam, and to prevent the responsiveness of the optical disc apparatus from being impaired.

Abstract: The invention related to a laser diode power control apparatus in an optical drive capable of driving an optical media by high-speed, which uses a fine-tuning pulse to provide a recording pulse type suitable for high-density optical media. The laser diode power control apparatus includes a pulse generating unit, a control unit, and a transmitting unit. The pulse generating unit generates a recording pulse for each channel. The control unit controls the pulse generating unit by determining whether to apply a fine-tuning pulse to the recording pulse for each channel based on the type of the optical medium and the driving speed of the optical drive for the optical medium. The transmitting unit transmits a power level for each channel according to the recording pulse output from the pulse generating unit.

Abstract: When the recording capacity of an optical recording medium is increased, both reproduction characteristics and a tilt margin are improved. Specifically, when a laser beam is projected onto an information recording layer of the optical recording medium to reproduce information, a laser beam having a wavelength of 400 to 410 nm is employed. In addition, an objective lens which converges the laser beam and has a numerical aperture NA of 0.70 to 0.90 is employed. The reproduction is started by projecting the laser beam. A reproduction signal obtained by projecting the laser beam is decoded by means of a PRML detection method to generate reproduction data of the optical recording medium. When the quality of the reproduction data deteriorates, the power of the laser beam is temporarily increased.

Abstract: A semiconductor laser unit includes a plurality of semiconductor laser elements arranged parallel with one another in a laser beam-emitting direction, and a base for positioning and fixing the plurality of semiconductor laser elements. The plurality of semiconductor laser elements are arranged such that a laser beam emitted from the semiconductor laser element greatest in astigmatism, of the plurality of semiconductor laser elements, is coincident in its axis with a reference axis of the base. In the case that the semiconductor laser unit is arranged on an optical head device, the focusing characteristic on the plurality of laser beams can be improved.

Abstract: An optical disc apparatus is provided, which comprising a laser light emitting portion for generating laser light for irradiating an optical disc, and a laser control portion for controlling a light emission operation of the laser light emitting portion. The laser control portion causes the laser light emitting portion to emit light with a first period during a first operation, and the laser control portion causes the laser light emitting portion to emit light with a second period during a second operation. The first period and the second period are different from each other.

Abstract: An optical disk drive for optimizing laser power to be used at the time of recording operation. In a DVD-R drive and a DVD-RW drive, a controller performs OPC to set recording power and records RMD serving as recording management data in an RMA serving as a recording management area. The RMD are verified. When the RMD can be read, the number of PI errors in the RMD is detected. If the number of PI errors is equal to or less than an allowable value, data are recorded in a data area at that recording power. If the number of PI errors exceeds the allowable value, OPC is again performed, to thereby reset the recording power.

Abstract: A system, for tuning a plurality of write strategy parameters of an optical storage device, includes: a run-length limited (RLL) meter for detecting a plurality of lengths, each length corresponding to a pit or a land on an optical storage medium accessed by the optical storage device; and a calculation module coupled to the RLL meter for performing calculations according to the lengths to generate a plurality of calculation results; wherein the write strategy parameters are tuned according to the calculation results.

Abstract: An optical disc apparatus and a method for performing optical power study thereof can prevent errors for a power study result, which may be generated in a condition that the output power of a laser diode (LD) is saturated at a high temperature, in which the power study detects output characteristics of the LD. The optical disc apparatus includes a laser output device which outputs a laser beam in response to a light output control signal, a sensor which detects some of the outputted laser beam to output a signal corresponding to the outputted laser beam, and a controller which applies the light output control signal of a certain range to the laser output device and which calculates characteristics of the laser output power which is outputted from the laser output device in response to the light output control signal, based on the output signals of the sensor, which correspond to the light output control signal, and whether the laser output device is in a saturated state.

Abstract: A data recording/reproducing apparatus wherein various data to be used for maintenance are measured, and parameters required for analysis of the maintenance data are prerecorded to realize prediction of the service life of a semiconductor laser and detection of occurrence of any trouble that may be derived therefrom. In this apparatus where data are recorded in and/or reproduced from a recording medium, the internal state of the apparatus is measured, then any abnormal state in the apparatus is detected on the basis of abnormal state decision data, and the detected state is transmitted to an external information processor. The apparatus comprises a means for measuring first data relative to the apparatus; a first memory means for storing second data to make a decision as to an abnormal state of the measured first data; a means for generating third data relative to maintenance of the apparatus on the basis of the first and second data; and an output means for delivering the third data as an output.

Abstract: A hologram recording apparatus for carrying out holographic recording by emitting a signal beam and a reference beam onto a holographic recording medium includes a laser light source configured to output a pulsed laser beam, a splitter configured to split the laser beam into a signal beam and a reference beam, a spatial light modulator configured to modulate the signal beam or both the signal beam and the reference beam, and a controlling unit configured to control the spatial light modulator to modulate at least one of the signal beam and the reference beam with a totally dark pattern for a predetermined period of time, wherein the predetermined period begins no later than the start of the risetime of a pulse of a laser beam output from the laser light source.

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: Disclosed herein is an optical recording medium recording apparatus, includes: an optical pickup section configured to irradiate laser light on an optical recording medium to perform recording or reproduction of information on or from the optical recording medium; a control section configured to control the optical pickup section; and a storage section configured to store in advance an evaluation function for adjusting the intensity of the laser light in response to reflected light of the laser light when information is to be recorded on the optical recording medium; wherein the control section being operable to interrupt a recording process of information onto the optical recording medium midway of the recording process and reproduce information recorded before the interruption and then adjust the evaluation function based on a detection result of reflected light upon the reproduction.

Abstract: A strategy process used for recording data on an optical disk is also used during DC erase is performed. Effects similar to those obtained in the case, in which a high frequency signal is superposed on a laser diode output current during the DC erase, can be obtained by performing the strategy process on the laser diode output current during the DC erase. This eliminates the necessity for generating high-level and high-frequency signals. Consequently, an apparatus can be constructed at low cost.

Abstract: A laser power control device for use in an optical recording and/or reproducing apparatus that records data on and/or reproduces data from an optical recording medium by driving a laser diode with a laser diode driver.

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: 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 and apparatus for recording information by irradiating light onto a medium to form a recorded domain, and method and apparatus for reproducing the recorded information are provided. In one example of the method, a plurality of light spots are modulated synchronously and irradiated onto a recording medium so that the plurality of light spots have an overlapped region on the recording medium. Since the profile of the total energy of the plurality of light spots is varied when the intensities of the plurality of light spots are modulated synchronously, it is possible to move the position where the total energy becomes maximum to any position on the optical recording medium. Thus, by moving the maximum point of the total energy of light spots in a cross-track direction, information can be recorded in a wobbled manner.

Abstract: If data is recorded using a disc with deviating characteristics and a recorder with deviating characteristics, data will not be appropriately recorded, and errors will occur in the read signal. Standard recording pulse parameters specifying recording pulse positions for plural possible mark length and space length combinations are read from a writable optical disc, these standard recording pulse parameters are then used for test writing, the standard recording pulse parameters are changed uniformly or individually, a best recording pulse parameter is thus obtained, and jitter can be reduced.

Abstract: An optical disk apparatus which records/reproduces data on/from a plurality of types of optical disks. The optical disk apparatus has a plurality of laser diodes. Two laser light rays emanating from two laser diodes are coupled together by means of a coupling prism. The thus-coupled laser light is radiated onto an optical disk. A photodetector is disposed in close proximity to the coupling prism. The coupling prism guides, to the photodetector, a laser light component of at least one laser light ray of the two laser light to be coupled together, the component having not been radiated onto the optical disk on an optical path. Laser light which is not radiated onto the optical disk on the optical path includes diffracted light other than a main beam emanating from the laser diode or laser beam which has not been subjected to coupling at the coupling surface of the coupling prism.

Abstract: An apparatus and method determining an optimum recording power suitable for a disc loaded in a disc drive. The apparatus includes a pickup unit and a control unit. The pickup unit records data in a predetermined area on the disc and reproduces the recorded data from the disc. The control unit controls the disc drive to record data in the predetermined area of the disc using a preset reference recording power. The control unit detects a plurality of recording powers using reproduction signals of the predetermined area reproduced from the pickup unit and one or more reference values, and decides an optimum recording power for the disc based on the detected plurality of recording powers. Thus, the recording power used by an active layer of the disc can be prevented from varying due to hardware error in the disc drive with respect to various kinds of discs.

Abstract: A laser driver drives a laser diode by producing a write strategy, that is, a recording waveform from a recording clock and a modulated signal. In one embodiment, a laser driver produces the waveform of a driving signal, which is used to drive a laser diode, using a record data signal that represents record data to be recorded on a recording medium. The laser driver comprises an internal clock production circuit that produces an internal clock synchronous with the record data signal, and a strobe circuit that strobes the record data signal according to the internal clock.

Abstract: A holographic ROM system of the present invention includes a holographic disk for storing information in a form of hologram; a pick-up module for optically reading the information stored in the holographic disk and producing an electrical signal in response to what has been read; and a control unit. The pick-up module has at least two light sources which are controlled by the control unit and a temperature measuring device for measuring an operating temperature of said at least two light sources, and the temperature measuring device transmits a temperature signal indicating the operating temperature to the control unit.

Abstract: A polarization split device that includes an optically isotropic substrate, an optically anisotropic film, and a diffraction grating. The optically anisotropic film is formed on the optically isotropic substrate. The diffraction grating includes first and second cyclically structural portions. The first cyclically structural portion is formed on a front surface of the optically anisotropic film such that a depression in a rectangular shape is cyclically arranged with a predetermined pitch. The second cyclically structural portion includes an optically transparent material having a refractive index approximately equivalent to a refractive index of the optically anisotropic film and is configured to cover the first cyclically structural portion. Diffraction light having a diffraction angle greater than a predetermined angle among diffraction light diffracted by the diffraction grating is inhibited from being discharged outside.

Abstract: An optical pickup apparatus is provided with two light sources; an objective lens for focusing light originating from each light source on an optical recording medium; a light separation optical element for transmitting or reflecting the light originating from each light source; a collimator lens for converting the light originating from each light source into a generally parallel beam; an upward-directing mirror for changing the optical path of the light originating from each light source by reflecting it; reflectors disposed between the light separation optical element and the respective light sources, for reflecting parts of light beams emitted from the light sources, respectively; photodetectors for detecting light beams reflected from the reflectors, respectively; and an APC circuit for controlling the power of the light beam emitted from each light source in accordance with a detection output of each photodetector.

Abstract: A method for establishing an optical connection between at least one optoelectronic component arranged in a first substrate and emitting or receiving optical radiation substantially perpendicular to a substrate surface of the first substrate, and at least one optical waveguide aligned with a first end substantially parallel to the substrate surface. The method comprises providing a second substrate that is transparent for at least one wavelength range of the optical radiation, and applying a layer of material on the second substrate. The layer is transparent, at least after structuring, for the wavelength range.

Abstract: A reverse pattern is formed in a track adjacent to a specified track on an optical recording medium with a predetermined light beam capable of writing large recording marks. Thereafter, a normal pattern is formed in an area, of an adjacent track, which is adjacent to the reverse pattern in the specified track with recording light beams of various strengths, the adjacent track being adjacent to the specified track. The specified track is read to detect a plurality of read-out signals according to individual light beam conditions. The adjacent track is read to detect a plurality of read-out signals according to individual light beam conditions. An optimum recording condition is determined for the specified track from the plurality of light beam condition and the read-out signals from the specified track and the adjacent track, and information is recorded in the specified track according to the optimum recording condition.

Abstract: In an optical recording/reproducing apparatus of the present invention, a semiconductor laser driver supplies a selected one of a plurality of drive currents, including at least a first-level drive current and a second-level drive current, to a semiconductor laser to control the emission of a laser beam by the laser. A current driver selectively outputs one of a plurality of increment currents to the laser driver in response to control signals, the plurality of increment currents including a first increment current supplied to the laser driver during an automatic power control process and a second increment current supplied to the laser driver during a special power setting process.

Abstract: A data assurance method controls an optical head according to the difference between the device temperature and the temperature of inserted removable optical storage media. A rate of temperature change c is calculated from the output of a temperature sensor which detects the device temperature, and then the temperature of the media is estimated. A transition is made to special processing, and a return is made from special processing in a state with a temperature difference to normal processing depending on the rate of temperature change. Consequently a return to normal processing can be made safely and quickly.

Abstract: The present invention relates to a method for controlling recording optical power. When a recording operation is paused, a playback signal characteristic for recorded data is detected. The recording optical power is controlled based upon the detected playback signal characteristic and hence the recording operation is resumed at the controlled recording optical power. Therefore, even though a characteristic of an optical pickup or disc varies when the recording operation is paused and resumed, an optimum recording operation can be performed and a playback characteristic for recorded data can be improved.

Abstract: A low voltage differential signaling transmitting circuit includes a driver circuit that outputs currents as differential signals from its pair of output terminals in accordance with a digital signal input to its input terminal, a bias circuit that supplies the driver circuit with a bias current so as to adjust values of the currents output from the driver circuit, a current/voltage conversion circuit that converts the currents output from the pair of output terminals of the driver circuit into voltages, and a receiver circuit that compares the voltages with each other and outputs a signal representing a result of the comparison. The bias circuit and the current/voltage conversion circuit are arranged on a same semiconductor chip.

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 multi-layered 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: In an optical disk apparatus, recording information by irradiating a laser light from a laser diode LD upon a recording surface thereof, while rotationally driving an optical disk by means of a spindle motor 207, being provided with a front monitor diode FMD for monitoring the laser light from the LD therein, a controller portion 205 detects deterioration of the laser diode, including the kink phenomenon, in particular, of loosing the linearity in the driving characteristic thereof caused due to driving under the condition of high temperature, by comparing a laser light output detected by the FMD to that, which is detected previously, within recording operation of the apparatus, and it also makes controls to lower the rotation velocity of the optical disk. This is suitable, in particular, to the optical disk apparatus of a super or ultra-thin type.

Abstract: A method is provided for recording data in a write-once type optical recording medium which can record data by forming a recording mark having a desired length and reduce jitter of a reproduced signal. The method comprises determining a pulse train pattern so that a level of a pulse is switched from the level corresponding to the level of the recording power Pw to the level corresponding to the level of the bottom power Pb in accordance with the length of a blank region to be formed immediately after formation of a first recording mark and the length of a second recording mark formed subsequent to the formation of the first recording mark.

Abstract: An edge position of a recording pulse is corrected according to multi-valued information for determining the width of a mark in an edge position correction circuit, thereby it is possible to form a mark edge in a correct position when a mark with any width is to be corrected to enable a correct multi-valued recording/reproducing.

Abstract: A light source drive which modulates a light source so as to cause the same to emit a light, includes: a superposition current generation part which generates a superposition current approximately corresponding to a charging/discharging current needed for a capacitance occurring in parallel to the light source for a predetermined time period near at least one of a rising-up part and a decaying-down part of a waveform of a drive current for the light source; and an addition/subtraction part which adds to or subtracts from the drive current the superposition current generated by the superposition current generation part.

Abstract: An optical information recording method of recording information on an optical information recording medium by irradiation of laser beam, the method comprises the steps of: forming a recording waveform which forms a first pit having a shortest pit length, by using a top pulse having a width narrower than a width of a channel clock cycle; forming a recording waveform which forms a second pit that is second shortest following the first pit, by using the top pulse and a terminal pulse having a width narrower than the width of the channel clock cycle; and forming a recording waveform which forms a pit that is longer than the second pit, by using the top pulse, the terminal pulse, and at least one multipulse formed between the top pulse and the terminal pulse. According to the method described above, pits having stable shape can be formed and thus jitter of reproduced signals can be reduced in an optical information recording medium having a narrow track pitch and high recording density.

Abstract: The present invention is directed to an optical head adapted for performing recording or reproduction of information signals with respect to an optical disc (102), which controls light coupling efficiency with respect to light beams irradiated onto the optical disc (102) by light coupling efficiency adjustable element such as a liquid crystal element (214), etc. in accordance with type of the optical disc (102), recording surface of multi-layer optical disc and/or operation mode to change power of light beams irradiated onto the optical disc (102) to a large extent without excessively increasing change quantity of output power of a semiconductor laser element (212). A beam splitter (218) divides incident light beams of P-polarized light at a predetermined ratio to allow the light beams thus obtained to be incident on a light detector (219) for disc surface power monitor.

Abstract: An optical recording method that performs recording by irradiating optical recording media with laser beam modulated in intensity based on a write waveform is provided. The write waveform has a plurality of write pulse blocks for forming write marks, and each write pulse block has at least one type of upward pulse. In the event that the width of said upward pulse is so narrow that the laser beam intensity corresponding to the peak intensity of that upward pulse cannot be obtained, the peak intensity of that upward pulse is increased so that, in said laser beam, the beam intensity it should have or a value close thereto is obtained. Thereby, good recording and playback characteristics can be obtained even when recording at a high transfer rate.

Abstract: It is an object of the present invention to provide a method of recording information to an optical recording medium that is suited to achieving high data transfer rates. The optical recording medium according to the present invention comprises a method of recording information to an optical recording medium where information is recorded by forming on the optical recording medium a plurality of recording marks selected from a group consisting of several types of recording marks each with different lengths, wherein a first recording mark and a second recording mark contained within said group are formed with the number of pulses and the pulse spacing in the laser beam set substantially equal to each other. Thus, even in the case that one clock period (T) is shortened to achieve high transfer rates, recording marks with good shapes can be formed. In addition, control is simplified and it is possible to reduce the cost of a drive to which the present invention is applied.