Abstract: A magnetic sensing element includes a composite film, a lower shield layer, and a lower electrode layer and an upper electrode layer for supplying a current perpendicular to the composite film. The composite film has an antiferromagnetic layer, a pinned magnetic layer, a nonmagnetic layer, and a free magnetic layer. The composite film has a top face and two side faces in a track width direction. Each of the two side faces has a bent position. The angle defined by the side face below the bent position and the top face is larger than the angle defined by the side face above the bent position and the top face. The bent portion preferably lies on the lower electrode layer or the lower shield layer.

Abstract: An optical disk device has a recording information management portion which detects a distribution of a recorded region R and an unrecorded region M based on reflection light received by an optical head and an access target setting circuit which determines an access target of an optical head so as to make access to a target position of a recording layer of an optical disk while avoiding the unrecorded region M based on the detected distribution of the regions. Since an access is made while passing through only the recorded region R, a servo operation can be stabilized.

Abstract: A laser power control apparatus and method prevent fluctuation in the level of laser power due to a difference between reaction speeds of an automatic power controller according to write speeds of a disc drive. In the apparatus and method, laser power can be automatically controlled to prevent a variation in the level of laser diode driving voltage in read power periods, according to the write speeds of a disc drive, in a write mode. Thus, it is possible to prevent unstable operations of a servo circuit due to a variation of the level of laser power and further, prevent deterioration in the quality of the servo circuit due to a variation in the level of a wobble signal, thereby stabilizing recording characteristics of the disc drive.

Abstract: An optical recording medium including a substrate having guide groove thereon; a first protective layer located overlying the substrate; a recording layer located overlying the first protective layer; a second protective layer located overlying the recording layer; a third protective layer of from 2 to 9 nm thick located overlying the second protective layer and comprising Si in an amount not less than 35 atomic percent; and a reflection layer including Ag in an amount not less than 95% by weight. An overcoat layer having a glass transition temperature of from 90° C. to 180° C. is preferably formed overlying the reflection layer. A method for manufacturing the optical recording medium is also provided.

Abstract: An optical recording and reproducing medium has grooves 2 formed along recording tracks and can be recorded and/or reproduced with irradiation of light L having a predetermined wavelength ?. When n assumes a refractive index of a medium extending from a light entrance end face to the grooves 2 of the optical recording and reproducing medium, a phase depth x of this groove 2 satisfies the following inequality: ?/16.14n?x??/4.99n and a ratio w/p between a width w of the groove 2 and a track pitch p satisfies the following inequality: 0.391?(w/p)?0.

Abstract: In an optical disk high-speed replaying/recording apparatus, a first read data quality determining section determines a quality of read second units of digital data. Upon determination that the quality of the second units of digital data is low, a first re-reading section re-reads the first units of digital data tracks, sectors, or data blocks in the second units at a third replay speed obtained by subtracting a first predetermined speed from a second replay speed. With this, the optical disk can be replayed at a speed higher than the normal replay speed, and reproduced data can be recorded on a writable optical disk except defective data caused by reproduction defects.

Abstract: A lens for an optical recording and reproducing system includes: a plane of incidence on which a light generated from a light source is made incident; a first reflection side for reflecting a light passing through a plane of incidence; and a second reflection side for reflecting again the light that has been reflected on the first reflection side, the second reflection side being formed to be an ellipsoid side, and the first reflection side and the second reflection side being coated with a reflection material. A very small optical system in its size and weight is possibly constructed, so that information recording and reproducing can be possible only with one focussing lens without a necessity of an objective lens. Accordingly, an ultra-thin optical recording and reproducing system of which height is remarkably reduced can be provided.

Abstract: An optical disk drive and recording power determination method determine the optimum power with consideration for the recording state of a base layer track when determining the optimum power by test recording before recording user data. After recording at a second recording power that is higher than a first recording power by a specific amount, recording is performed at a third recording power that is lower than the first recording power by a specific amount, and the first recording power is set to the recording power for data recording when a specified playback signal quality is achieved.

Abstract: The storage media recording/writing system includes a media drive circuit, a head retaining means, a head moving means, a head drive circuit, a signal processing circuit, and a controller to control these. The head drive circuit possesses a first semiconductor integrated circuit having an amplifier that amplifies the read signal from the head, and a second semiconductor integrated circuit placed between the first semiconductor integrated circuit and the signal processing circuit, which has a circuit that receives write data from the signal processing circuit and generates a drive signal to drive a write head. Further, the first semiconductor integrated circuit is mounted on a part near the front of the head retaining means, and the second semiconductor integrated circuit is installed on the side of the moving means.

Abstract: A semiconductor integrated circuit for an audio system includes a playback processing section for playing back at least an optical disk, a frequency measurement circuit for measuring a frequency of a radio signal from a tuner, a display control circuit for making a display device display at least the frequency of the radio signal, and a controller for controlling the playback processing section, the frequency measurement circuit, and the display control circuit, according to an external signal. The playback processing section, the frequency measurement circuit, the display control circuit, and the controller are formed on a single semiconductor chip.

Abstract: A controller for controlling interruptions and restarts when writing data to a recording medium by emitting a laser beam against the recording medium. The controller prevents buffer underrun errors. The laser beam is emitted at a high power level when writing data on the recording medium and at a low power read level when reading data from the medium. The writing of data is interrupted when there is a possibility of a buffer underrun error. When restarting data writing from where the interruption occurred, the laser beam is shifted from the read level to the write level before reaching the location at which the interruption occurred. This guarantees that the laser beam has the required power level when writing is restarted.

Abstract: Disclosed is a preamplifier circuit of a magnetic record regeneration apparatus with a write system and a read system, certainly verifying a write function in a short period of time. The preamplifier circuit includes, in the write system, a write driver; a current-voltage conversion circuit for converting the write current from the write driver into a corresponding voltage; a waveform shaping circuit for converting the output voltage from the current-voltage conversion circuit into a full-wave rectified waveform; a peak-hold circuit for holding a peak value of the output from the waveform shaping circuit; a filter circuit for outputting an average voltage of the output from the waveform shaping circuit; and a determination circuit for determining that the write driver is abnormal based on each output status of the peak-hold circuit and the filter circuit.

Abstract: When an action for turning off the power of a host computer is performed, the host computer transmits control information to a disk drive to the effect that chucking should be canceled. Accordingly, the disk drive cancels chucking of a disk and transmits information to the host computer to the effect that cancel has been completed. Receiving the information to the effect that chucking has been canceled, the host computer terminates a disk drive application, confirms that all of the started applications are completed, and then terminates OS (Operating System).

Abstract: A stabilization part stabilizes surface vibration of a flexible optical disk along a rotation axis direction of the optical disk by means of pressure difference of air flow created according to Bernoulli's law at a portion on which information writing/reading is performed, provided on a side of the optical disk opposite to a side on which information recording/reproducing is performed. In this case, areas are provide on the upstream side and down stream side along the disk rotation direction of the portion of the optical disk which is stabilized by said stabilization part, said areas of the optical disk not having pressure difference created thereon by the air flow.

Abstract: A write element includes a first pole pedestal and a second pole pedestal opposing the first pole pedestal and defining a write gap between the first and second pole pedestals. A first layer of CoFeON is film positioned between the first pole pedestal and the write gap. A second layer of CoFeON film is positioned between the second pole pedestal and the write gap.

Abstract: A focus search control unit for outputting an order to move an objective lens to the vicinity of a targeted position is provided with a trajectory generating unit for generating a position trajectory to move the objective lens such that the objective lens approaches the targeted position gradually. The position trajectory output from the trajectory generating unit is a position trajectory with which resonance frequency components that the lens moving unit has are removed or attenuated by making smooth the variation of acceleration of the objective lens moved by the lens moving unit. The position trajectory is defined by, for example, a function of third order or higher with respect to time.

Abstract: An optical disk device for recording data in an optical disk under ZCLV control is provided. The optical disk device divides the optical disk into a plurality of zones, and drives said optical disk at a linear velocity fixed in each zone but varied among the zones. At least one of the linear velocity and the number of zones of the optical disk is controlled in accordance with the amount of data to be recorded. Data recording time is reduced by dynamically changing at least one of the linear velocity and the number of zones of the optical disk in accordance with the amount of data to be recorded, rather than fixing the number of zones and the linear velocity thereof.

Abstract: Electronics are fitted in vehicles, such as boats, ships, trains, buses, lorries, normal cars etc. The electronic items are exposed to jolts and other non-uniform actions. Particularly with regard to jolts, electronic items or apparatuses in which there are also mechanical components are particularly exposed. This is particularly the case with CD players, CD-ROM players, hard disks and similar apparatuses, which besides very sensitive electronics also have very sensitive mechanics. To operate these installations optimally, dampening vibration transmission from the vehicle/ship/train/bus/car to the electro-mechanical component is achieved with a vibration damper having two springs arranged in two mutually perpendicular planes. One plane is parallel with the base. A first spring is fastened to the base. A second spring is fastened to the vibration sensitive item. The two springs are mutually connected.

Abstract: The present invention discloses a system for speed error compensation. A predetermined speed signal subtracts a feedback speed signal to generate a speed error signal, and a microprocessor receives the speed error signal and outputs a calculated result. A feedback controller receives the calculated result and generates a first tracking control effort signal. A feedforward controller receives the speed error signal and generates a second tracking control effort signal according to a DC steady state error in the speed error signal. An optical head module moves at an actual speed determined by the total of the first tracking control effort signal and the second tracking control effort signal. A gain controller generates the feedback speed signal according to an actual speed signal detecting from the actual speed.

Abstract: An optical disk device record data on a recordable or rewritable optical disk. After a pause and a restart in the constant angular velocity (CAV) method occurs predetermined times due to a cause of a recording error such as a buffer underrun, the data-recording by the CAV method is, for the first time, switched to the data-recording by the constant linear velocity (CLV) method at a recording velocity equal to or less than a recording velocity just before the last pause so as to provide a recording density equal to said constant recording density when said pausing is performed.