734 results about "Flying height" patented technology

A micro-actuator is comprised of a piezoelectric motor mounted on a flexure tongue with offsetting hinges, to perform a fine positioning of the magnetic read / write head. The substantial gain in the frequency response greatly improves the performance and accuracy of the track-follow control for fine positioning. The simplicity of the enhanced micro-actuator design results in a manufacturing efficiency that enables a high-volume, low-cost production. The micro-actuator is interposed between a flexure tongue and a slider to perform an active control of the fly height of the magnetic read / write head. The induced slider crown and camber are used to compensate for thermal expansion of the magnetic read / write head, which causes the slider to be displaced at an unintended fly height position relative to the surface of the magnetic recording disk. The enhanced micro-actuator design results in reduced altitude sensitivity, ABS tolerances, and reduced stiction. The controlled fly height of the magnetic read / write head prevents a possibility of a head crash, while improving the performance and data integrity.

A magnetic head includes a slider having an air bearing surface (ABS) and a trailing surface, with a transducer fabricated on the trailing surface. The transducer includes an adjunct pole disposed in a first general plane, the adjunct pole having a front edge that is recessed from the ABS and a rear edge. A main pole of the transducer is formed adjacent the adjunct pole, the main pole having a write tip that extends approximately to the ABS. A write coil having a first layer of turns is disposed in a second general plane below the adjunct pole. The magnetic head further includes a heating element, a portion of the heating element being disposed in the first general plane behind the rear edge of the adjunct pole.

A method adjusts a flying-height distance between a magnetic write head and a magnetic medium. The method includes positioning the write head in a location spaced from the magnetic medium by the flying-height distance. The write head includes a magnetic yoke and a proximal region in proximity to the magnetic medium. The write head further includes a resistive heater and at least a portion of the resistive heater is within the magnetic yoke and is in proximity to the proximal region. The resistive heater is configured to heat the proximal region. The proximal region has a coefficient of thermal expansion. The proximal region is configured to expand and to contract in response to a temperature of the proximal region. The method further includes flowing an electric current through the resistive heater. The method further includes controlling the electric current to adjust the temperature of the proximal region to selectively expand and contract the proximal region and thereby control the flying-height distance. Controlling the electric current includes pulsing the electrical current and adjusting a time interval between pulses.

A disk drive is disclosed comprising a disk having a plurality of tracks, and a head actuated over the disk. Control circuitry heats the head in order to reduce a fly-height of the head, and computes a target servo sector to begin a preheat period. The control circuitry decreases the heat so that the fly-height is increased during at least part of a seek operation to seek the head from a first track to a second track. When the head reaches the target servo sector, the control circuitry increases the heat to decrease the fly-height during the preheat period.

A disk drive is disclosed which generates a pole tip protrusion (PTP) measurement by performing a write operation to heat the transducer while measuring a fly height of the transducer. A first data sequence written to the disk is read without heating the transducer to generate a first signal measurement. A second data sequence is then written to the disk in order to heat the transducer, and the first data sequence is again read to generate a second signal measurement. The PTP measurement is then generated in response to the first and second signal measurements.

A read / write head for use in a data storage device to control the low dynamic flying height in order to achieve high data recording storage capacity of magnetic hard drives. The read / write head is designed for use in a data storage device that includes a storage medium having a recording surface. The head comprises a pole tip region and an actuator. In turn, the actuator includes an excitation source for generating a magnetic field, and a magnetostrictive plate for expanding in response to the magnetic field, resulting in a protrusion in a section of the pole tip region along a direction towards the recording surface, so that the head flies above the recording surface at a flying height lower than a nominal flying height.

A magnetic recording device includes a slider having an air bearing surface (ABS), a leading side, and a trailing side and a head residing on the slider. The head has a first magnetic transducer and a first heater for heating an area proximal to the first magnetic transducer. A first shield (S1) comprising a first material is on the leading side of the first magnetic transducer and a second shield (S2) comprising the first material is on the trailing side of the first magnetic transducer. A first pole (P1) comprising the first material is on the trailing side of the second shield (S2), and the first pole (P1) is between 0.6 micron and 2.0 micron thick; and the second shield (S2) is less than 0.6 micron thick. A hard disk drive includes the magnetic recording device.

A disk drive to reduce head instability during disk drive manufacturing is disclosed. The disk drive comprises: a disk; a dynamic flying height (DFH) read / write head; a flying height actuator to control the spacing between the DFH read / write head and the disk; and a controller. The controller controls operations in the disk drive including applying a sloped increasing power between a first voltage and a second voltage to move the DFH read / write head towards the disk.

A head for use in a drive includes a heating element capable of generating heat sufficient to cause the head to have a shape that is similar or identical to the shape that the head has when performing an operation (e.g. writing) on a recording medium in the drive. The heating element is activated when the operation is not being performed. Hence, a head generates the same amount (or similar amount) of heat and is therefore at the same temperature (also called “operating temperature”), regardless of whether or not an operation (such as writing) is being performed. Therefore, the head maintains a fixed shape or has a shape that varies minimally, within a predetermined range around the fixed shape, that in turn results in maintaining fly height (distance between the head and the recording medium). The heating element may be implemented to use loss mechanisms inherent in a write transducer, e.g. by providing a center tap to the write transducer. When using a center tapped write transducer, currents in phase with one another are provided to perform a write operation. When not performing the write operation, the same currents are provided, but out of phase.

A calibration disk includes calibration areas that allow a glide head to be calibrated as to the glide's head's avalanche height, fly height and the like. The calibration areas may be, for example, configured in a circumferential band (or, alternatively, a series of circumferential bands extending substantially concentric to one another), one or more spiral bands or some other suitable configuration. Such bands can, for example, extend from adjacent an outer diameter of the calibration disk to adjacent an inner portion of the calibration disk. Each of the circumferential bands is a textured area on the calibration disk having a given degree of composite roughness, as measured by the given circumferential band's average composite roughness height, and as such is referred to herein as a calibration band. Preferably, the given circumferential band is textured in a uniform manner, sufficient to produce a constant and continuous output signal from a sensor mounted on a glide head when the glide head flies lower than a maximum composite roughness height. Also preferably, the average composite roughness height within an individual calibration band is substantially uniform, and the average composite roughness height of each calibration band is slightly different from that of the other calibration bands.

Disclosed is a magnetic disk that has excellent durability, particularly excellent LUL durability, and excellent alumina resistance and has a high level of reliability under a low flying height of a magnetic head involved in a recent tendency toward a rapid increase in recording density and a very severe environment resistance requirement due to diversified applications. A magnetic disk (10) comprises a substrate (1) and at least a magnetic layer (6), a carbon-based protective layer (7), and a lubricating layer (8) provided in that order over the substrate (1). The lubricating layer (8) contains a compound that has a perfluoropolyether main chain in the structure thereof and has an aromatic group and a polar group at the end of the molecule.

An apparatus and method for automatically adjusting the gram load and static attitude in a head suspension assembly comprising one or more lasers, a fiber optic switch, a measurement apparatus and a computer control means. The fiber optic switch includes a plurality of fiber optic lines which direct the output of the laser to well-defined regions on the suspensions in a disk drive. Irradiation of the suspension by the laser causes a load change which alters the static attitude change in the slider. In the method of the present invention, the initial gram load or static attitude is measured by the measurement apparatus and the control means calculates how much energy is required to cause the change needed to achieve the desired condition. Other information, such as the type of laser to be used is also specified by the control means. The laser then delivers output to the suspension through the fiber optic line having an angled end and the static attitude or gram load is remeasured to determine if additional adjustment is required.

In a slider using thermal expansion type, being adjustable on a flying height thereof, having problems to be solved, i.e., to reduce the electric power consumption, and to lesson the heat load upon a reproducing element thereof, wherein a heating device 4 is located separating from tip portions of the recording and reproducing elements 2 and 3. Also, for deforming only the vicinity of the heating device 4 and the recording and reproducing elements 2 and 3, so as to protrude from, the heating device 4 and the recording and reproducing elements 2 and 3 are surrounded by a resin film 6 of small rigidity, thereby increasing an amount of protrusion of the recording and reproducing elements 2 and 3 per a unit of electric power, but without increasing temperature of the reproducing element 3, with an aim of the structure of cutting off the force from materials of circumferences against the deformation.

Provided is a magnetic disk comprising a lubricating layer formed of a lubricant. The lubricant constituting the lubricating layer has excellent properties, for example, excellent fluidity, surface energy, and CFT properties. By virtue of the excellent properties, the magnetic disk has a high level of reliability despite a low flying height of a magnetic head due to a recent rapid increase in recording density and a very severe environment resistance requirement due to diversification of applications. The magnetic disk comprises a substrate and at least a magnetic layer, a protective layer, and a lubricating layer provided in that order over the substrate. The lubricating layer is formed of a lubricant that is a mixture of a specific perfluoropolyether lubricant with a lubricant formed of a compound comprising perfluoropolyether groups having a perfluoropolyether main chain in the structure thereof and having a hydroxyl group at the end thereof, the perfluoropolyether groups being bonded to each other through a divalent linking group having at least two hydroxyl groups in the structure thereof.

Embodiments of the invention appropriately control the flying height of a magnetic head slider as necessary without making the magnetic head slider touch the magnetic disk. In one embodiment, when a magnetic disk drive is started, the level of electric power predefined for the ordinary temperature (room temperature) is read in from the internal memory of an MPU. A temperature sensor measures the internal temperature of the magnetic disk drive and sends it to the MPU. According to the temperature sent from the temperature sensor, the MPU calculates the level of electric power which should be applied to a flying height adjustment structure. According to the calculated electric power, the MPU increases or decreases the electric power applied to the flying height adjustment structure. At a flying height controlled (corrected) by the flying height adjustment structure, a magnetic head slider performs read / write on a magnetic disk.

The present invention relates to a system for determining whether the flying height of a read / write head above a disk in a disk drive is within an acceptable range, in substantially real time. The system relies on variations in read signal resolution with flying height to make the determination. In one embodiment, read signal resolution is measured and compared to a predetermined threshold value to determine whether the present flying height is in the desired range. In another embodiment, the number of peaks in a read signal that are detected (and / or not detected) by a detector is used to determine whether the head is in the proper flying height range. Because of read signal resolution effects, the number of detected peaks will decrease as the flying height of the head is increased. Means are also provided for postponing a transfer of data to / from the disk when it is determined that the head is not within the acceptable range.

A fly height controller (10FHC; 10FHC′) for controlling the fly height of a read / write head assembly (15) in a disk drive (20) is disclosed. A heat element resistor (30) is disposed within the read / write head assembly (15). The fly height controller (10FHC; 10FHC′) includes registers (32R, 32W) for storing digital data words corresponding to the desired drive levels to be applied to the heat element resistor (30) during read and write operations. The registers (32R, 32W) are selectively coupled to a steady-state digital-to-analog converter (DAC) (36), depending upon whether a read or write operation is occurring; the output of the steady-state DAC (36) is applied to a voltage driver (40), which in turn drives current into the heat element resistor (30). Overdrive and underdrive transistors (44P, 44N) are provided to overdrive and underdrive the input to the voltage driver (40) in transitions between read and write operations. An initial state register (50) receives a digital word indicating the desired current for the heat element resistor (30) when unselected; the output of the initial state register (50) is applied to an initial state DAC (52), which drives an initial state voltage driver (54). Control logic (35; 35′) controls whether the steady-state voltage driver (40) or initial state voltage driver (54) drives the heat element resistor (30). The fly height controller (10FHC′) may also be adapted to control the fly height of multiple read / write head assemblies (15) in a disk drive.

Methods, circuits, and systems for processing a preamble field in a read channel (e.g., in a magnetic storage device such as a hard disk drive). The methods generally include the steps of (a) reading the preamble field, wherein the preamble field comprises a repetitive bit pattern having a logical transition every x bit periods, where x is an integer of at least 3 when d is 0 or 1, or where x is an integer of at least d+2 when d is greater than 1, and (b) processing the repetitive bit pattern. The methods may further relate to processing the preamble for synchronization with the read channel and / or for measuring the fly height of a read / write head. The invention also relates to methods of enabling read channel synchronization and / or fly height measurement. The circuitry for fly height measurement generally includes (a) reading logic configured to read a preamble field from a read channel, wherein the preamble field comprises a repetitive bit pattern, (b) determination logic configured to determine a characteristic of the repetitive bit pattern, and (c) correlation logic configured to correlate the characteristic to the fly height. The systems generally comprise those that include a circuit embodying one or more of the inventive concepts disclosed herein. The present invention advantageously provides improved resolution of signals resulting from the preamble fields and of harmonics of said signals, and enables fly height measurement and improved channel synchronization without consuming dedicated tracks, platters, etc. on a magnetic recording medium.

Embodiments of the invention improve the power consumption and response speed of a heater for the gap flying height (hg) adjustment, to minimize an influence that the heater has on a life of a read element, and to provide a heater having resistance lines reduced in breaking and ensuring higher reliability. In one embodiment, a read / write element is formed near an air bearing surface (ABS) on a slider, and the circumference of the read / write element is filled with alumina. The read / write element includes an upper magnetic pole piece, a lower magnetic pole piece, a coil, and a resist filling around the coil, and a read element (MR) for performing reading, and an upper shield and lower shield for protecting the read element from an external magnetic field. A heater for adjusting the flying height is provided between the slider and the read / write element but near the read / write element. A temperature gradient relaxing material having a thermal conductivity higher than that of the heater and that of a material (alumina) filling around the heater is formed near the heater.

The invention discloses equipment and a method for proportionally remote controlling a vehicle and an unmanned aerial vehicle by touching on intelligent terminal. The method comprises the following steps of setting a direction speed control area, a speed gear adjusting area, a flying height control area and a mode selection key area on a touch screen of the intelligent terminal, wherein the key area comprises remote control selection keys of different equipment; meanwhile, setting a state display area on a display unit; detecting a touch gesture on the touch screen; making sure that the detected gesture is a slide gesture in a direction control touch area; according to the slide track, calculating the slide direction and the slide distance of the gesture; transmitting control information containing flying direction and speed to the remote controlled equipment. Compared with the prior art, the equipment and the method have the advantages that operation action on the equipment, such as remote control vehicle and the unmanned aerial vehicle, on the intelligent terminal is simplified, and the using experience of controlling the equipment through the intelligent terminal by a user can be greatly improved.

A thermal flying height adjustment slider capable of being mounted on a small-sized thin film magnetic head slider is provided wherein terminals of an energizer serving as a heater prevent corrosion of pole pieces and the number of terminals is reduced. In one embodiment, one of terminals of the energizer serving as the heater is electrically connected to the lower pole piece, so that a relay terminal for a heating device is used also as the terminal for preventing the corrosion of pole pieces.

A fly height controller (10FHC; 10FHC′) for controlling the fly height of a read / write head assembly (15) in a disk drive (20) is disclosed. A heat element resistor (30) is disposed within the read / write head assembly (15). The fly height controller (10FHC; 10FHC′) includes registers (32R, 32W) for storing digital data words corresponding to the desired drive levels to be applied to the heat element resistor (30) during read and write operations. The registers (32R, 32W) are selectively coupled to a steady-state digital-to-analog converter (DAC) (36), depending upon whether a read or write operation is occurring; the output of the steady-state DAC (36) is applied to a voltage driver (40), which in turn drives current into the heat element resistor (30). Overdrive and underdrive transistors (44P, 44N) are provided to overdrive and underdrive the input to the voltage driver (40) in transitions between read and write operations. An initial state register (50) receives a digital word indicating the desired current for the heat element resistor (30) when unselected; the output of the initial state register (50) is applied to an initial state DAC (52), which drives an initial state voltage driver (54). Control logic (35; 35′) controls whether the steady-state voltage driver (40) or initial state voltage driver (54) drives the heat element resistor (30). The fly height controller (10FHC′) may also be adapted to control the fly height of multiple read / write head assemblies (15) in a disk drive.

A mechanism for maintaining a constant fly-height of a slider comprises a capacitive fly-height change sensor and an electrostatic fly-height controller. The capacitive fly-height change sensor is configured for coupling with the slider, which is in a head gimbal assembly. The capacitive fly-height change sensor is also configured for measuring a capacitance between the slider and a surface of a disk through the use of a fly-height change sensing signal, and outputting a sensor voltage which is substantially proportional to a sensed change in said capacitance. The electrostatic fly-height controller is coupled with the capacitive fly-height change sensor and configured to couple with the slider. The electrostatic fly-height controller is configured to process the sensor voltage into a fly-height control signal for electrostatically maintaining a constant fly-height of the slider relative to the surface of the disk.

A system and method for determining head-disk contact (HDC) in a magnetic recording disk drive uses the signal from the magnetoresistive (MR) read head. The analog MR signal is digitized and input to a digital signal processor with circuitry and / or software for integrating the signal amplitude over a low-frequency range. The calculated value from the integration when the slider is out-of-contact with the disk is a reference value. The same integration is then performed during operation of the disk drive and the measured value is compared to the reference value. If the measured value exceeds the reference value by some predetermined amount, this is an indication of the onset of HDC or that HDC has occurred. The method can be used in head-disk testers to facilitate the design and testing of disk drive components, such as slider-suspension assemblies and fly-height actuators located on the slider to alter the head-disk spacing, and in disk drives to control fly-height actuators and to take corrective action prior to HDC.

A method and a device for airborne laser scanning flying height change real-time compensation can eliminate adverse effect of flying height change to a laser scanning point cloud distribution area and cloud density of a laser scanning point. When the flying height of an airborne platform is changed, a flying height change value is acquired by a global position system(GPS) / inertial navigation system(INS)integrated measurement device, the value of a scan field angle which can keep the width of a scanning stripe unchanged and the value of a laser pulse frequency which can keep the laser scanning point cloud density unchanged are calculated in a flying height compensation controller. A rotating prism photoelectric shaft angle encoder measures and obtains a real time rotating angle of a rotating prism and offers the real time rotating angle of the rotating prism to the flying height compensation controller, a square signal which is identical with an expect laser pulse frequency value is outputted only within a scope of the required scan field angle and offered to a laser pulse transmitter, thus a laser transmitter can launch a laser pulse of the corresponding frequency. By using the compensation method, the flying height change of the airborne platform can not affect the laser scanning point cloud distribution area and cloud density of a laser scanning point permanently.