Patent application number | Description | Published |
20090185306 | GAP SERVO CONTROL METHOD AND APPARATUS IN NEAR-FIELD OPTICAL DISC DRIVE - A gap servo control method and apparatus for increasing a disturbance cancellation capability and decreasing the occurrence of an overshoot in a near-field optical disc drive include: generating an actuator driving signal of a transient response process by using a signal obtained by removing a disturbance contained in the gap error signal using a first band when a level of a gap error signal reaches a first level; and generating the actuator driving signal of the transient response process by using a signal obtained by removing the disturbance contained in the gap error signal using a second band when the level of the gap error signal reaches a second level. | 07-23-2009 |
20100053710 | APPARATUS FOR RECORDING/REPRODUCING HOLOGRAPHIC DATA AND METHOD OF ADJUSTING POSITION OF RECORDING LAYER - An apparatus for recording/reproducing holographic data and a method of adjusting a position of a recording layer. While an objective lens focusing first and second lights having different wavelengths on a holographic data storage medium including first and second reflective layers reciprocatingly moves in a direction of an optical axis, a focus movement unit, which moves a focus of the second light in the direction of the optical axis until a time difference between a first detection signal generated when the first light is reflected from the first reflective layer and a second detection signal generated when the second light is reflected from the second reflective layer becomes a value corresponding to a position of a desired recording layer, is controlled to move a focal position of the second light so that the focal position of the second light can be adjusted to the position of a desired recording layer. | 03-04-2010 |
20100061203 | METHOD AND APPARATUS FOR RECORDING AND/OR REPRODUCING DATA INTO AND/OR FROM OPTICAL DISK - Provided are a method and apparatus for recording and/or reproducing data into and/or from an optical disk. The apparatus includes a reference beam optical system to form a focus of a reference beam in an optical data storage layer of the optical disk and including an objective lens; a signal beam optical system to form a focus of a signal beam in the optical data storage layer and also including the objective lens; and a servo optical system to project a servo beam onto the optical disk, receiving a reflection servo beam which is reflected on the optical disk, and performing focusing and tracking control on the objective lens. The reference beam optical system includes a first focus mover to move the focus of the reference beam, and the signal beam optical system includes a second focus mover to move the focus of the signal beam. The data is recorded into a plurality of recording layers in the optical data storage layer by moving a first focus position, at which the foci of the reference beam and the signal beam are located, in a thickness direction of the optical data storage layer, which is a focusing direction. | 03-11-2010 |
20100061210 | OPTICAL DISC AND RECORDING/REPRODUCING METHOD AND APPARATUS FOR THE OPTICAL DISC - An optical disc, and a recording/reproducing method and apparatus to record information on the optical disc. The optical disc includes an optical information storage layer, including a layer format region and a user data region. The layer format region is divided into virtual layers that are disposed at different depths. The virtual layers include layer information to distinguish the virtual layers from one another. | 03-11-2010 |
20100110846 | METHOD AND APPARATUS FOR CONTROLLING POSITION IN WHICH DATA IS TO BE RECORDED - A method and apparatus to control a position in which data is to be recorded on a holographic data recording medium by using interference between a reference light and a signal light, the method including: irradiating the reference light and the signal light on the holographic data recording medium; generating a focus error signal that indicates a distance difference between a first focus corresponding to a focus of the reference light on the holographic data recording medium and a second focus corresponding to a focus of the signal light on the holographic data recording medium, based on information about a reflective signal light generated when the irradiated signal light is reflected from a reflective transmission layer of the holographic data recording medium; and moving the second focus to a position of the first focus, based on the focus error signal. | 05-06-2010 |
20110103204 | METHOD AND APPARATUS FOR COMPENSATING FOR DEFECT OF STORAGE MEDIUM - An apparatus for compensating for a defect of a storage medium of an optical driving includes a memory to store sample values of a servo driving signal during at least one track sampled by a first signal and cycle information about the first signal; a servo driving signal estimator to estimate a servo driving signal during at least one next track using the sample values, the cycle information about the first signal, and cycle information based on a second signal; and a transmitter to transmit the servo driving signal estimated by the servo driving signal estimator to a servo driver of the optical driving device during a defect section of the storage medium; wherein the first signal is synchronized with a radial direction of the storage medium; and the second signal has a frequency higher than the first signal. | 05-05-2011 |
20120194113 | Apparatus and method of estimating inductance of permanent magnet synchronous motor - A method of estimating inductance of a permanent magnet synchronous motor (PMSM) includes injecting a signal having a frequency differing from an operating frequency of the PMSM into the PMSM during sensorless operation, sensing magnitudes of current responses to the injected signal, and estimating an inductance value at which the magnitude of the sensed current response is minimal to be an actual inductance value of the PMSM, thereby estimating inductance used in the PMSM regardless of position estimation error of the PMSM and thus more accurately and reliably estimating inductance of the PMSM. | 08-02-2012 |
20140028237 | INVERTER CONTROL APPARATUS AND CONTROL METHOD THEREOF - An inverter control apparatus and a control method thereof are provided. The inverter control apparatus and a control method thereof stably operate a three-phase motor using a capacitor having a small capacitance for a DC link. The inverter control apparatus includes a current sensor to sense an output current of the inverter, a voltage sensor to sense a DC-link voltage of the inverter, and a controller to generate an average of a periodically varying rotor based q-axis current boundary value based on the output current and the DC-link voltage to generate a current reference on the basis of the average of the rotor based q-axis current boundary value, and to drive a three-phase motor based on the current reference. Stabilized variable speed control of a motor by using a small-capacitance capacitor for a DC link of an inverter is performed and reliability of an inverter circuit improved. | 01-30-2014 |