Class / Patent application number | Description | Number of patent applications / Date published |
324210000 | Magnetic information storage element testing | 27 |
20080290863 | Open Write-Head-Cable Test Method and Detector - A storage drive implements a method for operating the storage drive between a plurality of operational modes. For a test mode of the storage drive, a write current driver circuit and a test current sensor are electrically connected to the write head, wherein the test current sensor generates a sense signal indicative of a degree of a flow of a test current through the write head to thereby facilitate a detection of any presence of an open write condition of the storage drive (i.e., any impedance condition impeding a flow of a write current through the write head). For a write mode of the storage drive, the write current driver circuit is electrically connected to the write head and the test current sensor is electrically disconnected from the write head, wherein the write head records data on a magnetic media based on a flow of the write current through the write head. | 11-27-2008 |
20090140732 | Low cost simplified spectrum analyzer for magnetic head/media tester - An electronic component tester characterizes electronic components such as magnetic head/media components measure performance parameters such as signal-to-noise ratio and overwrite evaluation. The electronic component tester has a tester process controller and a spectrum analyzer. The tester process controller generates calibration and control signals for the electronic component tester. The spectrum analyzer is in communication with electronic components such as magnetic head or media components to receive a response characterization signal resulting from a stimulus signal applied to the electronic components. The spectrum analyzer then determines a frequency spectrum of the response characterization signal. The spectrum analyzer is also in communication with the tester process controller for transferring the frequency spectrum to the tester process controller. The spectrum analyzer receives the calibration and control signals from the tester process controller for removing effects of an image frequency of the frequency spectrum and determining noise bandwidth of the frequency spectrum. | 06-04-2009 |
20090146652 | Slider tester - A slider tester includes a driving unit that rotates a test medium, a set plate that detachably supports a slider as a single body, and an investigating apparatus that is electrically connected to the slider supported by the set plate and investigates the characteristics of the slider. A movable support part | 06-11-2009 |
20090146653 | Slider tester - A slider tester includes a driving unit that rotates a test medium, a set plate that detachably supports a slider as a single body, and an investigating apparatus that is electrically connected to the slider supported by the set plate and investigates the characteristics of the slider. A movable support part | 06-11-2009 |
20090201015 | METHOD AND DEVICE FOR DETECTING FERROELECTRIC POLARIZATION - An information storage device comprises a ferroelectric media and a cantilever including a tip extending from the cantilever toward the ferroelectric media, and a capacitive sensor formed over the cantilever. The tip applies a probe voltage to the ferroelectric media and the capacitive sensor vibrates according to a response of the ferroelectric media to the probe voltage. Circuitry determines a polarization of the ferroelectric media based on the vibration of the capacitive sensor. | 08-13-2009 |
20090219018 | METHOD FOR INSPECTING MAGNETIC CHARACTERISTICS OF A PLURALITY OF THIN MAGNETIC HEADS BY MEANS OF LOCAL APPLICATION OF MAGNETIC FIELD - A method for inspecting magnetic characteristics of a thin film magnetic head that is arranged in a row bar includes: a step of preparing a row bar having sliders including a thin film magnetic head formed therein and lapping guides having magnetoresistance effect; a step of preparing a magnetic field applying row bar having first and second magnetic field applying elements; a first positioning step in which said magnetic field applying row bar is arranged opposite to said row bar; a second positioning step in which a relative movement between said magnetic field applying row bar and said row bar is made so that at least one of said lapping guides exhibits a largest output voltage; and a measurement step in which a relationship between the intensity of the magnetic field and an output voltage of a magnetic field sensor is obtained. | 09-03-2009 |
20090243602 | METHOD AND APPARATUS FOR TESTING CHARACTERISTIC OF MAGNETIC HEAD - The method for testing a characteristic of a magnetic head is performed in the form of a wafer, especially in a heating state and a cooling state. The method for testing a characteristic of a magnetic head, in which a wafer including a dummy read-element having a size equal to that of a completed read-element, a product read-element and a heat conductive section being provided in the vicinity of the dummy read-element is tested as a test sample, comprises the steps of: applying an external magnetic field to the test sample; bringing a heat conducting member into contact with the heat conductive section so as to heat or cool the dummy read-element via the heat conductive section; and testing an electromagnetic conversion characteristic of the dummy read-element in a heating state or a cooling state. | 10-01-2009 |
20090256557 | TESTING METHOD OF MAGNETIC HEAD BY USING INDUCTANCE - It is an object of the present invention to provide a method for investigating magnetic domains, the method capable of easily grasping behavior of the magnetic domains in a head manufacturing process, and further to provide a testing method of a magnetic head capable of evaluating whether the writing performance of the magnetic head is good or not. The method for investigating magnetic domains comprises supplying direct current (DC) to a coil of an electromagnetic transducer provided in a magnetic head for writing data onto a magnetic recording medium; measuring an inductance of the electromagnetic transducer at each current value while varying the current value of the direct current; and investigating behavior of magnetic domains in a magnetic core of the electromagnetic transducer based on a relationship between the current values and the inductances. The testing method of a magnetic head comprises evaluating whether writing performance of the magnetic head is good or not, based on a relationship between the current values and the inductances. | 10-15-2009 |
20100109656 | Magnetic Tunnel Junction and Memristor Apparatus - A magnetic memory device includes a magnetic tunnel junction having a free magnetic layer having a magnetization orientation that is switchable between a high resistance state magnetization orientation and a low resistance state magnetization orientation and a memristor solid state element electrically coupled to the magnetic tunnel junction. The memristor has a device response that is an integrated voltage versus an integrated current. | 05-06-2010 |
20110057649 | METHOD AND ITS APPARATUS FOR DETECTING DEFECTS - In the present invention, to make corrective matching thereof, it is designed as follows; position effect of defects coordinates, which are output from an inspection apparatus, is allowed, coordinates of inspected data are mutually corrected, and a state of coincidence or non-coincidence among a plurality sets of inspected data is output or displayed. Inspection data is designed to include kinds, kinds difference and dimension of defects. A state of coincidence or non-coincidence between inspected data is designed to be output or displayed appropriately, by kinds or dimensions, or by a grouping thereof, of a defects object. The same sample is inspected by every time of passing a production step, and a state of data increase or decrease, or coincidence or non-coincidence between the inspected data is designed to be output or displayed. | 03-10-2011 |
20120056618 | WRITE HEAD TESTER USING INDUCTANCE - A write head is tested by measuring the effect that magnetic fields have on the inductance of the write head. For example, a perpendicular write head may be placed in a magnetic field with a first angle, e.g., non-parallel and non-perpendicular, to the air bearing surface and the inductance is measured. After altering the angle of the magnetic field the inductance is again tested. In another embodiment, the angles may be parallel and perpendicular to the air bearing surface. The difference in the inductance value can be used to determine a characteristic of the write head, such as the presence of a recording pole. In some embodiments, the inductance may be measured while applying a bias current to the write head while the write head is in an external magnetic field. | 03-08-2012 |
20120056619 | WRITE HEAD TESTER USING INDUCTANCE - A write head is tested by measuring the effect that magnetic fields have on the inductance of the write head. For example, a perpendicular write head may be placed in a magnetic field with a first angle, e.g., non-parallel and non-perpendicular, to the air bearing surface and the inductance is measured. After altering the angle of the magnetic field the inductance is again tested. In another embodiment, the angles may be parallel and perpendicular to the air bearing surface. The difference in the inductance value can be used to determine a characteristic of the write head, such as the presence of a recording pole. In some embodiments, the inductance may be measured while applying a bias current to the write head while the write head is in an external magnetic field. | 03-08-2012 |
20120146631 | TESTING APPARATUS WITH READ HEAD HOLDER HAVING A GAS JET - A test apparatus can test a read head and/or a disk. The test apparatus includes a rotatable spindle adapted to hold the disk, and a holder oriented to hold the read head with its air bearing surface adjacent the major surface of the disk during testing. The holder includes a channel with a first side wall. The channel defines a channel longitudinal axis parallel to the first side wall. The channel also defines a lateral direction that is normal to the first side wall. A first gas jet points into the channel and impinges upon a top face of the read head. | 06-14-2012 |
20120249130 | Method for measuring longitudinal bias magnetic field in a tunnel magnetoresistive sensor - A method for measuring longitudinal bias magnetic field in a tunnel magnetoresistive sensor of a magnetic head, the method includes the steps of: applying an external longitudinal time-changing magnetic field onto the tunnel magnetoresistive sensor; determining a shield saturation value of the tunnel magnetoresistive sensor under the application of the external longitudinal time-changing magnetic field; applying an external transverse time-changing magnetic field and an external longitudinal DC magnetic field onto the tunnel magnetoresistive sensor; determining a plurality of different output amplitudes under the application of the external transverse time-changing magnetic field and the application of different field strength values of the external longitudinal DC magnetic field; plotting a graph according to the different output amplitudes and the different field strength values; and determining the strength of the longitudinal bias magnetic field according to the graph and the shield saturation value. | 10-04-2012 |
20120274317 | Method of testing anti-high temperature performance of a magnetic head and apparatus thereof - A method of testing anti-high temperature performance of a magnetic head comprises applying a second magnetic field with different intensities in a second direction and the changing first magnetic fields in a first direction, and measuring a plurality of second output parameter curves; and judging whether a variation that is beyond an allowable value is presented on the second output parameter curves, thereby screening out a defective magnetic head, therein the first direction is perpendicular to the air bearing surface of the magnetic head, and the second direction is perpendicular to the shielding layers of the magnetic head. The present invention can screen out defective magnetic heads that possess poor anti-high temperature performance without heating the magnetic head and with high precision. | 11-01-2012 |
20130154628 | METHOD FOR JUDGING COERCIVE FORCE OF MAGNETIC RECORDING MEDIUM - A method for judging a coercive force of a magnetic recording medium, so recording magnetic information can be formed in either a low coercivity magnetic medium or a high coercivity magnetic medium by using a magnetic head. A magnetic information recording step writes magnetic information in the magnetic recording medium by alternately using a first write current suitable for writing in the low coercivity magnetic medium and a second write current suitable for writing in the high coercivity magnetic medium. A magnetic information reproducing step reproduces the magnetic information written in the magnetic recording medium. A judging step makes a judgment on a coercive force of the magnetic recording medium by way of comparing a first reproduced output A of the magnetic information written with the first write current and a second reproduced output B of the magnetic information written with the second write current. | 06-20-2013 |
20130257421 | METHOD AND SYSTEM FOR PERFORMING ON-WAFER TESTING OF HEADS - A method and system for testing a read transducer are described. The read transducer includes a read sensor fabricated on a wafer. A system includes a test structure that resides on the wafer. The test structure includes a test device and a heater. The test device corresponds to the read sensor. The heater is in proximity to the test device and is configured to heat the test device substantially without heating the read sensor. Thus, the test structure allows for on-wafer testing of the test device at a plurality of temperatures above an ambient temperature. | 10-03-2013 |
324211000 | Memory core storage element testing | 2 |
20130057265 | STRESSED MAGNETORESISTIVE TAMPER DETECTION DEVICES - A tamper sensing system mounted with respect to a protected structure so as to have corresponding stress changes occur therein in response to selected kinds of tamperings with said protected structure comprising a first pair of stress affected magnetoresistive memory devices each capable of having a magnetic material layer therein established in a selected one of a pair of alternative magnetization states if in a first kind of stress condition and of being established in a single magnetization state if in an alternative second kind of stress condition, and the magnetic material layer in each having a magnetization in a first direction in one of the pair of alternative magnetization states and in a second direction in that remaining one of the pair of magnetization states. A first magnetizing electrical conductor extends adjacent to each of the first pair of stress affected magnetoresistive memory devices to establish said magnetic material layer in that one of said pair of alternative magnetization states thereof so as to have its said corresponding magnetization be oppositely directed with respect to said magnetization of that other. The first pair of stress affected magnetoresistive memory devices can each be provided by a spin dependent tunneling device having differing numbers of magnetization states available thereto depending on whether being in differing ones of alternative stress conditions | 03-07-2013 |
20140139209 | MAGNETIC AUTOMATIC TESTING EQUIPMENT (ATE) MEMORY TESTER - Several novel features pertain to an automatic testing equipment (ATE) memory tester that includes a load board, a projected-field electromagnet, a positioning mechanism and a memory tester. The load board is for coupling to a die package that includes a magnetoresistive random access memory (MRAM) having several cells, where each cell includes a magnetic tunnel junction (MTJ). The projected-field electromagnet is for applying a portion of a magnetic field across the MRAM. The portion of the magnetic field may be substantially uniform. The positioning mechanism is coupled to the electromagnet and the load board, and is configured to position the electromagnet vertically about (above/below) the die package when the die package is coupled to the load board. The memory tester is coupled to the load board. The memory tester is for testing the MRAM when the substantially uniform portion of the magnetic field is applied across the MRAM. | 05-22-2014 |
324212000 | Dynamic information element testing | 8 |
20090085561 | METHOD AND APPARATUS FOR TESTING A MAGNETIC HEAD - A testing apparatus for a magnetic head tests electromagnetic conversion characteristics of the magnetic head by causing a magnetic head | 04-02-2009 |
20090128142 | Media defect removal in disk drive head testing - A method for testing a hard disk drive is described. The method includes determining a number of defects associated with a portion of recordable media associated with a hard disk drive. The method further includes comparing the number of determined defects to a threshold number of defects and provided the number of determined defects is greater than the threshold number of defects, determining that the portion of the disk comprises disk defects. | 05-21-2009 |
20110210723 | Method of performing electrostatic discharge testing on a payment card - Methods of performing electrostatic discharge testing on a transaction card are disclosed. A transaction card may be placed on an insulated surface. A grounding probe may be placed at a first location on the transaction card. A discharge probe may be charged to a known voltage level. The discharge probe may then be discharged at a second location on the transaction card. A discharge wave shape may be recorded from the ground probe, and one of a pass condition and a fail condition may be assigned based on at least the value of the known voltage level as compared to a reference voltage level. The first location and the second location may each be selected from a plurality of areas on the transaction card. | 09-01-2011 |
20120105056 | APPARATUS FOR SUPPORTING A DISK DRIVE, DISK DRIVE TEST APPARATUS AND METHOD OF TESTING A DISK DRIVE - There is disclosed apparatus for supporting a disk drive, disk drive test apparatus and a method of testing a disk drive. The apparatus for supporting a disk drive includes: a housing, a slot for receiving a disk drive, and a plurality of isolators. The slot is received in the housing and has a longitudinal axis. The isolators are disposed between the slot and the housing for isolating the slot from the housing. The isolators are arranged with respect to the longitudinal axis such that the slot has a low rotational stiffness in the direction of the longitudinal axis relative to the rotational stiffness in at least one other direction. | 05-03-2012 |
20120200287 | SPINSTANDS FOR TESTING A HEAD GIMBAL ASSEMBLY - There is disclosed a spinstand for testing a head gimbal assembly. The spinstand includes a gripper operable to grip the head gimbal assembly and a load pick device operable to hold a head gimbal assembly and to move the head gimbal assembly into an exchange position where it can be gripped by the gripper. In the exchange position part of the load pick device registers with the gripper and another part of the load pick device is spaced from the gripper so as to form a space between, in which space at least part of the head gimbal assembly is located in use. | 08-09-2012 |
20120268112 | MAGNETIC SENSOR AND A METHOD AND DEVICE FOR MAPPING THE MAGNETIC FIELD OR MAGNETIC FIELD SENSITIVITY OF A RECORDING HEAD - The invention provides a method and apparatus for scanning a read/write head of a hard disk drive during manufacture. The method comprises: providing a magnetic sensor; moving the magnetic sensor relative to and in close proximity to the read/write head under test; obtaining measurements from the head under test or the sensor, representing a two-dimensional magnetic map; processing the map to obtain an accurate map of the head sensitivity of the head under test from which the key performance characteristics of the head can be obtained. | 10-25-2012 |
20130063139 | METHOD AND ITS APPARATUS FOR INSPECTING A MAGNETIC HEAD DEVICE - An apparatus for inspecting a magnetic head device inspects an effective track width of a write track of each of magnetic head devices formed on a row bar in order to measure a two-dimensional distribution of magnetic fields generated by the magnetic head devices formed on the row bar while the apparatus is not affected by an external environment. The apparatus has a tray unit, a stage unit, a sample receiving and delivering unit, a magnetic field measuring unit and an effective track width measuring unit on a vibration isolation unit that blocks a vibration from the outside of the apparatus. The tray unit, the stage unit, the sample receiving and delivering unit, the magnetic field measuring unit, the effective track width measuring unit and the vibration isolation table are covered with a sound insulation unit that blocks noise from the outside of the apparatus. | 03-14-2013 |
20160195591 | APPARATUS FOR TESTING SAMPLE PROPERTIES IN A MAGNETIC FIELD | 07-07-2016 |