Abstract: A display apparatus can include a substrate having a penetrating area and a separating area, the penetrating area including a substrate hole, a first buffer layer having a first-buffer lower layer, and a first-buffer upper layer, a first thin film transistor including a first semiconductor pattern, a first gate electrode, and a first source electrode and a first drain electrode, a first interlayer insulating film; a second interlayer insulating film, an opening extending through the second interlayer insulating film, the first interlayer insulating film, the first gate insulating film and the first-buffer upper layer, and a separation structure in the opening, the separation structure including a first separation layer having a same stacked structure as the first-buffer upper layer, a second separation layer having a same stacked structure as the first gate insulating film, and a third separation layer having a same stacked structure as the first gate electrode.

Abstract: A hard disk drive includes a magnetic head, at least one disk and a controller. A location signal is recorded on the at least one disk for determining a location of the magnetic head in relation to the at least one disk. The controller controls the location of the magnetic head based on the location signal decoded through the magnetic head. At least one of frequency and amplitude of the location signal is variable.

Abstract: A hard disk drive using an increase in servo address mark delays to create a touchdown flag in response to a slider making contact with a rotating disk surface while accessing a track. This may be used particularly when the track being accessed is located away from the Inside Diameter (ID). The hard disk drive may further use resistive heater electrical readings to determine the touchdown flag for track locations near the ID. The hard disk drive may be calibrated during manufacture and/or may be recalibrated in the field with this method. The calibrated hard disk drive is a product of this method. The method may be used during normal access operations and/or may be embodied as a program system residing in computer readable memory for instructing a computer operating the hard disk drive, where the computer and/or the memory may or may not be included in the hard disk drive.

Abstract: Provided is an apparatus and method of adjusting reference clock frequency in a disk drive. The reference clock frequency adjustment method includes; measuring each servo sector detection time interval, generating an error signal by subtracting initially set reference time interval information between servo sectors from the measured servo sector detection time interval information, and adjusting the reference clock frequency using the error signal such that a constant number of reference clock pulses are generated in each servo sector detection time interval regardless of variation in each servo sector detection time interval.

Abstract: A hard disk drive using an increase in servo address mark delays to create a touchdown flag in response to a slider making contact with a rotating disk surface while accessing a track. This may be used particularly when the track being accessed is located away from the Inside Diameter (ID). The hard disk drive may further use resistive heater electrical readings to determine the touchdown flag for track locations near the ID. The hard disk drive may be calibrated during manufacture and/or may be recalibrated in the field with this method. The calibrated hard disk drive is a product of this method. The method may be used during normal access operations and/or may be embodied as a program system residing in computer readable memory for instructing a computer operating the hard disk drive, where the computer and/or the memory may or may not be included in the hard disk drive.

Abstract: A hard disk drive with a controller that determines a position error signal gain. The position error signal gain is determined from a total servo loop gain and a function that is defined by a slope of a line of A and B servo bits measured at N off-track positions. The function determines an actual plant gain and thus provides a more accurate position error signal gain.

Abstract: A disturbance compensation determination apparatus, a related method, a computer readable medium storing a computer program related to the method, and a disk drive comprising the apparatus are provided. The disturbance compensation determination apparatus includes a disturbance observer (DOB) receiving a control input signal and a servo output signal of a plant, wherein the DOB calculates and outputs a current estimated disturbance value. The apparatus also includes a disturbance evaluation unit selectively changing a current disturbance compensation (DC) mode, wherein selectively changing the current DC mode comprises evaluating an accumulated estimated disturbance value in accordance with a condition corresponding to the current DC mode. In addition, the apparatus includes a switching unit selectively providing the current estimated disturbance value to a control loop of the plant in accordance with the current DC mode as selectively changed by the disturbance evaluation unit.

Abstract: A method of determining a size of an error generated in a servo sector, a write control method of controlling whether to write data to data sectors successive to a servo sector according to the size of the error generated in the servo sector therein, a HDD using the write control method, and a recording media storing computer programs for executing the methods. A method of determining a size of an error generated in a servo sector of a HDD includes: reading servo information from the servo sector in which the error was generated; and determining the size of the error by the number of corresponding bits that differ from each other between the read servo information and a normal servo information.

Abstract: A hard disk drive with a controller that determines a position error signal gain. The position error signal gain is determined from a total servo loop gain and a function that is defined by a slope of a line of A and B servo bits measured at N off-track positions. The function determines an actual plant gain and thus provides a more accurate position error signal gain.

Abstract: Provided are an apparatus and method of controlling a motor by compensating for recurring false speed errors generated in a direct current (DC) motor. The apparatus includes a learning control unit adapted to calculate recurring false speed errors related to a mechanical tolerance associated with the motor in each one of a plurality of controlling sections associated with a single rotation of the motor, and generate a corresponding reference speed for each controlling section, and a motor control unit adapted to control the rotational speed of the motor in relation to a speed error defined by a difference between the reference speed for each controlling section and an actual measured speed of the motor for each controlling section.

Abstract: A hard disk drive includes a magnetic head, at least one disk and a controller. A location signal is recorded on the at least one disk for determining a location of the magnetic head in relation to the at least one disk. The controller controls the location of the magnetic head based on the location signal decoded through the magnetic head. At least one of frequency and amplitude of the location signal is variable.

Abstract: A hard disk drive that includes a voice coil motor controlled by a servo. The servo provides a driving signal that has multiple sinusoidal waveforms. The multi-sinusoidal waveforms minimize seek time and vibrations in the drive.

Abstract: A hard disc drive (HDD) data read control apparatus, medium, and method reading data from a disc having non-uniform track-to-track spacing. The data read control method of the HDD, in which data is read from a disc including non-uniform track-to-track spacing, includes seeking a target track by adopting an off track amount applied to a previously followed track, and reading the data while following the sought target track. Accordingly, production yield can be increased by making failure processing unnecessary even if a track-to-track spacing of a HDD is non-uniform.

Abstract: A method and apparatus to safely repress disturbances from being applied to a system from the surroundings in which the system is used. The method of adaptively repressing disturbances includes estimating frequency components of a disturbance applied to a system in a user environment; and optimizing parameter values determining characteristics of a disturbance compensating servo control loop including a disturbance observer, based on the estimated frequency components of the disturbance.

Abstract: In a method of measuring track widths in a hard disk drive a plurality of estimation values are calculated based on differences in intensity between a plurality first measurement signals produced in relation to a head of the hard disk drive based on a plurality of burst signals stored in servo sectors of a track when the head moves along the track on a first side of a center of the track, and a plurality of second measurement signals produced in relation to the head of the hard disk drive based on the plurality of burst signals when the head moves along the track on a second side of the center of the track opposite the first side. The estimation values are then normalized, and excessive variation in the track widths is detected based on the normalized estimation values.

Abstract: A method, medium, and apparatus for controlling a spindle motor of a disk drive. Particularly provided is a method, medium, and apparatus changing a current gain of a spindle motor driver according to the operating environment of the spindle motor. The method of controlling the spindle motor, using the current gain change of the spindle motor driver, includes monitoring a spindle drive control signal indicating the operating environment of the spindle motor and changing a current gain of the spindle motor driver based on the indicated operating environment.

Abstract: The invention applies to servo controllers for at least the voice coil motor of a hard disk drive. Today, many control algorithms require 80 to 90 percent of the sampling period to complete their calculation of the next control, making computation time delay no longer negligible. The invention accommodates the transport delay, such as computation time delay, into the state estimator and into the whole control system. Experimental results using a commercial hard drive, as well as simulation results, show that the invention's method effectively improves the hard disk drive control system stability by increasing the phase margin and gain margin. The invention includes the method of operating the servo-controller, as well as the apparatus implementing that method. The invention also includes hard disk drives containing servo-controllers implementing the method, and program systems residing in accessibly coupled memory to a computer within the servo controller implementing the method.

Abstract: A hard disk drive apparatus to control a flying height of a magnetic head and a method thereof are provided. The hard disk drive apparatus includes a disk, a magnetic head to read data from the disk or to record data on the disk, a flying height maintaining unit to control a flying height of the magnetic head and to uniformly maintain the flying height above the disk, and a controller to control the flying height maintaining unit to maintain a first height as the flying height of the magnetic head in a seek mode, wherein the first height is greater than a second height at which a write operation or a read operation is performed by the magnetic head.

Abstract: A hard disk drive that includes a voice coil motor and a micro-actuator. The micro-actuator is controlled by a servo that utilizes a micro-actuator controller and a corresponding micro-actuator transfer function. The servo enters a mode to self-determine at least one transfer function coefficient of the micro-actuator controller.

Abstract: A disturbance compensation determination apparatus, a related method, a computer readable medium storing a computer program related to the method, and a disk drive comprising the apparatus are provided. The disturbance compensation determination apparatus includes a disturbance observer (DOB) receiving a control input signal and a servo output signal of a plant, wherein the DOB calculates and outputs a current estimated disturbance value. The apparatus also includes a disturbance evaluation unit selectively changing a current disturbance compensation (DC) mode, wherein selectively changing the current DC mode comprises evaluating an accumulated estimated disturbance value in accordance with a condition corresponding to the current DC mode. In addition, the apparatus includes a switching unit selectively providing the current estimated disturbance value to a control loop of the plant in accordance with the current DC mode as selectively changed by the disturbance evaluation unit.