| Class / Patent application number | Description | Number of patent applications / Date published |
|---|
| 369130260 | Setting light beam power level | 26 |
| 20110228652 | Slider For Heat Assisted Magnetic Recording Including A Photo Detector For Monitoring Laser Power - An apparatus includes a slider including an air bearing surface and a waveguide configured to receive light from a light source, a sensor positioned to receive a portion of light emitted by the light source prior to the light exiting the slider at the air bearing surface, and a controller controlling the light source power in response to a characteristic of the sensor. | 09-22-2011 |
| 20120134246 | HARD DISK DRIVE APPARATUS WITH THERMALLY ASSISTED HEAD - A hard disk drive includes a recording medium and a thermally assisted type magnetic head. The controller determines one output current of a photodiode as a first saturated output current, the one output current being defined where temperature measured by a temperature sensor is a first temperature and where signal-to-noise-ratio (SNR) of the reproducing signal current of the reproducing element is saturated with respect to an increase in output current of the photodiode, and another output current of the photodiode as a second saturated output current, the another output current being defined where temperature measured by the temperature sensor is a second temperature, which is different from the first temperature, and where SNR of the reproducing signal current of the reproducing element is saturated with respect to an increase in the output current of the photodiode. A target saturated output current at operation temperature is estimated from operation temperature measured by the temperature sensor during the hard disk device operation, the first and second temperatures, and the first and second saturated output currents; and the driving current of the laser diode is controlled in order to obtain the estimated target saturated output current. | 05-31-2012 |
| 20120176874 | LIGHT SOURCE UNIT INCLUDING A PHOTODETECTOR, AND THERMALLY-ASSISTED MAGNETIC RECORDING HEAD - A light source unit includes a light source and a photodetector. The light source has an emission part for emitting light. The photodetector has a light receiving surface for receiving the light emitted from the emission part, and detects the light. The light source unit further includes a grating made of metal and disposed to extend along the light receiving surface. The grating includes a plurality of line-shaped portions that each extend in a direction intersecting the direction of travel of the light and that are located at positions different from each other along the direction of travel of the light. | 07-12-2012 |
| 20120182843 | DEVICES AND METHODS FOR PROTECTING LASER DIODES FROM ELECTROSTATIC DISCHARGE - In accordance with certain embodiments, an apparatus has a depletion-mode transistor electrically connected to a laser diode. The transistor provides a low impedance path for diverting electrostatic current away from the laser diode. In accordance with certain embodiments, a method for protecting a laser diode from an electrostatic charge includes providing a transistor that is electrically connected to a laser diode and has a drain and a source. The method further includes redirecting the electrostatic charge through a low impedance path from the drain to the source during a powered-on state. | 07-19-2012 |
| 20120201108 | TRANSDUCER HEAD TEMPERATURE MONITORING - Changes in the thermal boundary condition near a close point of an ABS to a media indicate proximity of the ABS with the media. Before contact, heat conduction from the ABS is primarily through convective and/or ballistic heat transfer to air between the ABS and the media. After contact, heat flux primarily flows from the ABS to the media through solid-solid conductive contact. Further, a light source within a HAMR transducer head may create additional thermal variations within the transducer head. These thermal variations create temperature variations within the transducer head. Two resistance temperature sensors on the transducer head at varying distances from the close point and/or light source measure these temperature variations. A temperature difference between the two resistance temperature sensors indicates proximity of the close point to the media and/or light output. | 08-09-2012 |
| 20130044575 | METHOD FOR DETECTING PROTRUSION HEIGHT OF MAGNETIC HEAD SLIDER HAVING THERMALLY ASSISTED HEAD - A magnetic head slider includes a near-field light generator, an incorporated heater is activated to thermally-expand the magnetic head slider so that a first protrusion is generated on the air bearing surface, and a second protrusion protruding from the first protrusion is generated by a thermal expansion of the near-field light generator. A standard signal is written to a recording medium with a predetermined magnetization. A relation between a residual magnetization of the standard signal and a power of the heater is obtained by lowering the magnetization of the standard signal by heating the recording medium with the near-field light while light output of laser light is maintained to be constant and the power of the heater is varied. Further, a relation between the first spacing and the residual magnetization is obtained. A value of the first spacing is obtained as a protrusion height of the second protrusion from the first protrusion when the second protrusion contacts the recording medium, the value of the first spacing being determined where an absolute value of a change rate of the residual magnetization is less than a predetermined standard value. | 02-21-2013 |
| 20130077453 | DISK DRIVE CALIBRATING A LASER WRITE POWER FOR HEAT ASSISTED MAGNETIC RECORDING - A disk drive is disclosed comprising a head actuated over a disk, wherein the head comprises a laser for heating the disk while writing data to the disk. The disk drive receives write commands, and increases a power of the laser to a write power for heating the disk while writing data to the disk. A calibration interval is adjusted based on the power applied to the laser over time, and the write power is calibrated at the calibration interval. | 03-28-2013 |
| 20140301173 | DIFFERENTIAL LASER DIODE DRIVER APPARATUS AND SYSTEMS - Apparatus and systems create differential drive signals suitable for HAMR data recording. A laser diode differential driver provides heating current pulses at a time Φ | 10-09-2014 |
| 20140347965 | DISK DRIVE CALIBRATING DYNAMIC FLY HEIGHT WRITE PROFILE FOR FLY HEIGHT ACTUATOR - A disk drive is disclosed comprising a disk and a head actuated over the disk, the head comprising a fly height actuator (FHA). The disk drive further comprises control circuitry including disk access circuitry, wherein during a calibration operation, the disk access circuitry is configured into a calibration mode that increases a heating of the head, and a fly height of the head is measured periodically to generate periodic fly height measurements that vary due to the heating of the head. A dynamic fly height (DFH) write profile is generated based on the periodic fly height measurements. During a write operation, the disk access circuitry is configured into a write mode and a DFH control signal is generated and applied to the FHA based on the DFH write profile. | 11-27-2014 |
| 20150009787 | VARIABLE BIT ASPECT RATIOS IN MAGNETIC MEDIA - An apparatus comprises a write transducer, an energy source, and a controller. The write transducer is configured to write data to a magnetic recording medium, and the energy source is configured to heat the magnetic recording medium while it is being written to by the write transducer. The controller is coupled to the write transducer and configured to adjust at least an operating power of the energy source to selectably cause bits having variable bit aspect ratios to be written to the magnetic media. | 01-08-2015 |
| 20150016237 | METHOD FOR FABRICATING A PATTERNED COMPOSITE STRUCTURE - The embodiments disclose a patterned composite magnetic layer structure configured to use magnetic materials having differing temperature and magnetization characteristics in a recording device, wherein the patterned composite magnetic layer structure includes magnetic layers, at least one first magnetic material configured to be used in a particular order to reduce a recording temperature and configured to control and regulate coupling and decoupling of the magnetic layers and at least one second magnetic material with differing temperature characteristics is configured to control recording and erasing of data. | 01-15-2015 |
| 20150109892 | DUAL THERMAL SENSOR FOR HAMR WAVEGUIDE POWER MONITOR AND INTEGRATION WITH THE CONTACT SENSOR - Embodiments of the present invention generally relate to a HAMR device having two temperature sensors. The first temperature sensor is disposed adjacent a waveguide and is about two or more micrometers away from an air bearing surface. The first temperature sensor has a length, a width and a thickness, and the length is greater than the width and the thickness. The length of the first temperature sensor is substantially perpendicular to the waveguide. | 04-23-2015 |
| 20150332725 | CONTROLLING LASER OUTPUT IN A HAMR DEVICE - A method of controlling laser output in a heat assisted magnetic recording device can be performed by control circuitry in a data storage device. The method includes measuring a temperature, measuring laser output power of a laser, determining a power error by subtracting an optimal laser output power from the measured laser output power and comparing the power error to at least one threshold to determine whether an applied current to the laser needs to be adjusted. The at least one threshold is related to how great the power error can be while maintaining the integrity of data on a recording medium. | 11-19-2015 |
| 20150364152 | LASER OPTICAL POWER MONITORING USING THERMAL SENSOR OF A HEAD TRANSDUCER - A light source is configured to produce light, a waveguide is optically coupled to the light source and configured to direct the light to an intended focus location, and a slider is configured to use the light as an energy source for heating a region of a magnetic recording medium. A thermal sensor is situated on the slider at a location outside of a light path that includes the intended focus location. The thermal sensor is configured for sensing a short time constant change in temperature resulting from light source heating of the thermal sensor, wherein the sensed change in thermal sensor temperature is representative of optical intensity of the light delivered to the intended focus location. | 12-17-2015 |
| 20160012863 | MAGNETIC RECORDING AND REPRODUCING DEVICE AND MAGNETIC RECORDING AND REPRODUCING METHOD | 01-14-2016 |
| 20160035383 | THERMAL-ASSISTED MAGNETIC RECORDING DEVICE CAPABLE OF WRITING MAGNETIC PATTERNS ON LOWER MULTI-STEP DRIVING SIGNALS - According to one embodiment, there is provided a magnetic disk device including a light irradiation element and a control unit. The light irradiation element is configured to irradiate a magnetic disk with light according to a driving signal. The control unit is configured to lower, in multistep manner, active level of the driving signal contributing intensity of the light when a low frequency pattern of write data is recorded into the magnetic disk. | 02-04-2016 |
| 20160064029 | APPARATUS WITH FIRST AND SECOND CLOSE POINTS ON MEDIA-FACING SURFACE OF MAGNETIC HEAD - A magnetic head includes a read transducer and a write transducer at a media-facing surface of the magnetic head. The magnetic head includes at least one heater that causes heat deformation at the media-facing surface in response to different first and second energizing currents. The first energizing current results in a first close point between the media-facing surface and a recording medium. The second energizing current results in a second close point between the media-facing surface and the recording medium. The second close point is at a different location in the media-facing surface than the first close point. | 03-03-2016 |
| 20160148635 | HEAT ASSISTED MAGNETIC RECORDING FOR BIT-PATTERNED MEDIA - A heat-assisted magnetic recording (HAMR) device includes a controller that selects a power for operating a heat source for a data write to a target data track. According to one implementation, the controller selects the power based on an assessment of whether the target data track is bounded by any data-storing tracks. A first power is selected when the data track is not bounded by any data-storing tracks and a second lower power is selected when the data track is bounded by one or more data-storing tracks. In another implementation, the controller writes to different partitioned regions of a storage media with different powers of the heat source. The controller selects a storage location for data based on an expected write error rate and environmental conditions within the HAMR device. | 05-26-2016 |
| 20160148636 | LASER POWER OPTIMIZATION FOR HEAT ASSISTED INTERLACED MAGNETIC RECORDING - A storage device disclosed herein stores data on a storage media using interlaced magnetic recording (IMR) and it includes a storage controller configured to determine power levels applied to the power source such that power levels applied to heat various tracks can be different from each other. An implementation of the storage device determines the track density, linear densities and power levels for even and odd tracks in IMR HAMR for the storage media. | 05-26-2016 |
| 20160148637 | LASER POWER OPTIMIZATION FOR HEAT ASSISTED INTERLACED MAGNETIC RECORDING - A storage device disclosed herein stores data on a storage media using interlaced magnetic recording (IMR) and it includes a storage controller configured to determine power levels applied to the power source such that power levels applied to heat various tracks can be different from each other. An implementation of the storage device determines the track density, linear densities and power levels for even and odd tracks in IMR HAMR for the storage media. | 05-26-2016 |
| 20160189741 | THERMAL MANAGEMENT OF LASER DIODE MODE HOPPING FOR HEAT ASSISTED MEDIA RECORDING - A method and apparatus provide for determining a temperature at a junction of a laser diode when the laser diode is operated in a lasing state that facilitates heat-assisted magnetic recording, comparing the junction temperature and an injection current supplied during the lasing state to stored combinations of junction temperature and injection current, and determining a likelihood of mode hopping occurring for the laser diode during the lasing state based on the comparison to stored combinations of junction temperature and injection current. | 06-30-2016 |
| 369130270 | Based on referenced test signal | 5 |
| 20110205861 | LIGHT SOURCE POWER CONTROL FOR HEAT ASSISTED MAGNETIC RECORDING (HAMR) - Apparatus and method for light source power control during the writing of data to a storage medium. In accordance with various embodiments, a data recording head is provided having a magnetic transducer and a light source. The light source is driven at a first power level to irradiate an adjacent storage medium prior to the writing if data to the medium using the magnetic transducer. The first power level is insufficient to alter a magnetization state of the medium. The light source is subsequently transitioned to a higher, second power level to irradiate the storage medium during the writing of data to said medium using the magnetic transducer, the second power level being sufficient to alter said magnetization state of the medium. | 08-25-2011 |
| 20150380029 | METHOD OF ASSESSING RECORDING CHARACTERISTICS OF THERMALLY ASSISTED MAGNETIC HEAD - Using a thermally assisted magnetic recording head, reference signals are recorded into a magnetic recording medium; reproduction signal intensity of the reference signals is measured in a state where the thermally assisted magnetic head has been moved in the track width direction from the track width center of the track where the reference signals are recorded; a mean signal output of each sector in the track where the reference signals are recorded is calculated from the measurement results of the reproduction signal intensity of the reference signals; and the recording characteristics of a thermally assisted magnetic head are evaluated based upon the mean signal output of the sectors. | 12-31-2015 |
| 20150380040 | NEAR-FIELD TRANSDUCER EFFICIENCY MONITORING SYSTEM - A system may have a data storage medium that contains at least one data bit that is accessed by a transducing head that has a near-field transducer. A controller can be connected to the transducing head and store a plurality of near-field transducer operating currents in a memory. The controller may identify a change in efficiency of the near-field transducer from the plurality of near-field transducer operating currents. | 12-31-2015 |
| 20160019922 | METHOD OF SETTING FLYING HEIGHT AND FLYING HEIGHT SETTING DEVICE - While a plurality of drive currents for flying height setting with current values smaller than a tentative optimum drive current are supplied to a light source, respectively, heater power is supplied to a heater part, and touch down of a thermally-assisted magnetic recording head is detected. Tentative optimum heater power is determined based on a correlation between the heater power when the touch down is detected and each drive current for flying height setting. The tentative optimum drive current is supplied to the light source part; the tentative optimum heater power is supplied to the heater part; a reference signal is recorded in a magnetic recording medium; and flying height of the thermally-assisted magnetic recording head is set by determining whether or not the reference signal is recorded with the desired signal intensity. | 01-21-2016 |
| 20160055881 | Adaptive HAMR Laser Power Data Storage Device - A data storage device and associated methods may provide at least a data storage medium that is separated from a heat assisted magnetic recording data writer and is connected to a controller. The controller can be configured to change a laser power of the heat assisted magnetic recording data writer in response to a tested bit error rate of a median data track of a plurality of adjacent data tracks reaching an identified threshold. | 02-25-2016 |
