Abstract: An optical information recording and reproducing method for recording or reproducing information by irradiating pulsed laser diode light from a laser diode (LD) light source in which the resistance value of the LD light source is measured in an operating state, the measured LD light source resistance value is compared with a target resistance value, and the LD light source is heated when the LD light source resistance value is higher than the target resistance value, in order to maintain the LD light source resistance at a specified value or less.

Abstract: Disclosed data recording techniques prevent extremely decreasing writing/reading speed due to consecutive defects, which often occur when using a disk of large storage capacity, while allowing the size of a spare area used for alternate processing of a recordable optical disk to be changed. The disclosed data recording method comprises receiving from a higher-level device a write command to write data at a first address in a user area; writing the data at the first address; and reading the written data to thereby judge whether or not the first address is defective. If the first address is defective, a second address in a spare area is determined by use of a flag value that has been written to a lead-in area or a lead-out area at the time of initialization; and the data is written at the second address received from the higher-level device.

Abstract: An optical disc apparatus in which a bias of a focusing error signal is changed to a value according to a recording power at timing corresponding to a predetermined address position before starting the recording and a defocus of an opposite polarity is preliminarily caused so as to set off a defocus which occurs at the start of the recording.

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

Abstract: It is to provide an optical disc recording apparatus and a recording power control method that are adapted to high-speed recording and can set an optimal erasing power with high accuracy. A test writing signal detector reproduces a test writing signal of a predetermined mark length or space length with varied power, and detects the number of error mark signals and an amplitude value of an envelope. A controller obtains a first threshold Pe0 of the erasing power based on the number of error mark signals in a region where laser power is low, and obtains a second threshold Pe1 of the erasing power based on the amplitude value in a region where the laser power is high. Then, the controller sets an optimal value of the erasing power from an average value of the first and second thresholds.

Abstract: The present invention provides a thin optical disc drive whose impact resistance performance is improved. An under cover 19 is provided with a collision evasion hole 21 at a position corresponding to an end of an optical head housing 25. Moreover, a bottom cover 4 is provided with an impact force buffering member 22 at a position corresponding to the collision evasion hole. When an impact force acts on an optical disc drive 1, the impact force to the optical head housing 25 is buffered by the structure. Consequently, it is possible to prevent the optical head 8 from being damaged, and it is possible to improve the reliability of the optical disc drive 1.

Abstract: An optical disk apparatus for enabling to insert a multi-layered optical disk therein, which has plural numbers of recording layers, comprising: a spindle motor 42; an optical pickup 2; and a system controller 100 for controlling the optical pickup to move into a radial direction of the optical disk, as well as, for controlling the optical pickup so that a light-beam irradiated therefrom is focused upon either one of the plural numbers of recording layers of the optical disk, wherein when it is determined that the target layer to be accessed lies on a layer different from that, upon which the optical pickup focuses the light-beam at present, the light-beam irradiated from the optical pickup is shifted to the target layer, after being moved into a radial direction of said optical disk on the layer, upon which the light-beam irradiated therefrom is focused at present, up to an information recording area where the information of the target layer is recoded.

Abstract: In response to the trend toward the increase in the number of data layers of optical discs, the invention provides a data erasure method and its optical disc apparatus that enable faster data erasures with a simpler configuration. Test erasures are performed on the test areas T of data layers of an optical disc while the power level Pe of data erasure laser light and the defocus amount ?f of the data erasure laser light from a target data layer are changed. Based on the results of the test erasures, the optimal erasure condition that enables a simultaneous data erasure from the greatest number of data layers is determined. Based on the determined optimal erasure condition, then, the optimal erasure sequence that enables data erasure from all of the data layers with the fewest number of times is determined.

Abstract: Pulses modulated between the erase power and the bottom power are used instead of cooling pulses for an optical disk medium that needs a write strategy with 4-valued power levels. Consequently, pulse instruction lines for the cooling pulses, power level instruction lines, and corresponding current source within the laser driver can be omitted. Decrease in size and lower power consumption can be accomplished.

Abstract: A Spare Area kept unused on a disk is available for use other than spare processing, or Defect Management process, and compatibility of the disk is at least secured between different recording apparatuses. This is implemented by recording a SWP_PAC cluster defined as a new item and by recording address information of used addresses in a PAC or TDDS area.

Abstract: An optical disc apparatus for enabling reduction of fluid noises accompanying with disc rotation, effectively, comprises a tray 5 provided to be able to comes in/out into/from said housing freely, a unit mechanism 5 provided together with the tray, in one body, a turntable 9a provided on the unit mechanism and configured to support a disc thereon, to be rotatable freely, a plural number of wall portions 5b to 5d formed on the tray surrounding the disc supported on the turntable from an outer periphery thereof, each of which has configuration like an arc around a rotation center of the turntable, a pickup 10 for doing straight-line motion within along a radius direction of a disc 4, and an opening 56, which is provided on the wall portion 5e locating at the position on the moving track of the pickup, for maintaining movement of the pickup, wherein the wall portion 5e is moved or stepped back to a side of an outer periphery of the turntable comparing to other wall portions.

Abstract: Provided is an optical disk drive including: an actuator for driving an objective lens for applying a beam from a laser to an optical disk to cause a focal point of the beam to move in a focus direction; and a servo controller for receiving an input of a focus error signal and driving the actuator to control a focusing position of the beam, which includes: a compensation unit for generating a drive signal for the actuator based on the focus error signal; a noise detection unit for detecting a noise component by changing a limiter characteristic according to a frequency of the drive signal; and a correction unit for correcting the drive signal by subtracting the noise component from the drive signal. Accordingly, an influence of a tracking error signal leaking into the focus error signal in a focus servo system can be reliably suppressed.

Abstract: In a prior art slim-type high speed rotation optical disk apparatus, the side wall of the bottom chassis is bent at a bending point toward the side of the optical disk according to the configuration of the corner air window section of the chassis. According to the present invention, this bent side wall is formed so as to have a first vertical wall which is adjacent to the bending point and a second vertical wall which is adjacent to and lower than the first vertical wall. This constitutes an L-shaped vertical wall in the air window section of the bottom chassis, resulting in reduced noise.

Abstract: The present invention makes it possible to reproduce reproduction images without a break without having to use any additional identification information even when real-time recorded data is not completely continuous. A control circuit references a data identification flag (“Recording Type”) which is attached to each sector of reproduction data to indicate the type of recorded data, and counts the number of sectors to which the data identification flag representing real-time recorded data is attached. When the count is not smaller than a threshold value, the control circuit reproduces all the sectors of the target reproduction block in a real-time reproduction mode. In the real-time reproduction mode, the control circuit masks a portion of reproduction data that is found to be defective, changes the value of the defective data to 0 (zero), and transfers the resulting reproduction data to a host device.

Abstract: For the purpose of suppressing an increase of temperature of a laser element, in an optical disc drive, even in case when recording/reproducing at such a low double speed that almost no expectation can be made upon the effect of the convection cooling due to circulating flow of an air, which is generated by rotation of a disc, and in particular, the structure for fixing both end portions of a main shaft, which is engaged with a transfer mechanism for moving an optical pickup into the disc radial direction, through the optical pickup, between two (2) pieces of shafts for supporting the optical pickup, one of which forms the main shaft, onto connector portions to be engaged with the both end portions of the main shaft, upon a mechanical chassis, on which is mounted at least a disc rotation mechanism, etc.

Abstract: Bandwidth is secured for a read signal transmission line by matching the characteristic impedance of the read signal transmission line with the output impedance of a photodetector of an optical pick up, while at the same time securing bandwidth for the photodetector. In an optical disc drive according to an embodiment of the present invention, each line forming a differential transmission line is divided into a plurality of lines of the same quantity, the quantity being two or more, at or near a connection point between a flexible line and the optical pick up.

Abstract: A method and optical disc apparatus for evaluating a quality of a read signal adapted to the PRML method by evaluating a binary code decoded from the read signal obtained by a head, in which an error bit sequence having one bit edge shift from the binary code is generated, a Euclidian distance is calculated on both a correct bit sequence and the error bit sequence with respect to a predetermined target signal level, assuming that the binary code is the correct bit sequence, a Euclidian distance difference between the Euclidian distance on the correct bit sequence and the Euclidian distance on the error bit sequence is calculated, an average Euclidian distance from the target signal level is calculated, a normalized sequence error is calculated, the binary code is evaluated using the normalized sequence error.

Abstract: To prevent the degradation in read access performance to replacement data caused by not selecting appropriate replacement clusters and to suppress the waste of the number of DFL registrations. Attention is paid to the usage direction of a user data area and that of a replacement area, and in the case where one CRD-type DFL registration can be made collectively in the sequential defect management processes, a replacement area of which the usage direction is the same as that of the user data area is selected.

Abstract: An optical disc apparatus in which a bias of a focusing error signal is changed to a value according to a recording power at timing corresponding to a predetermined address position before starting the recording and a defocus of an opposite polarity is preliminarily caused so as to set off a defocus which occurs at the start of the recording.

Abstract: A method for adjusting recording power of an optical disk apparatus having an output circuit that outputs recording light onto a test writing area of an optical disk, and a control circuit that adjusts the recording power of the recording light outputted from the output circuit, the method including the steps of causing the control circuit to erase a recording mark recorded onto the test writing area, to record a recording mark onto the test writing area in constant recording power lower than threshold power for starting a recording operation, and to record a recording mark onto the test writing area while changing the recording power.