JP2007294034A - Disk drive device and test method in its design - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To verify easily that clearance is kept in design of TFC (Thermal Flyheight Control). <P>SOLUTION: In this HDD design, a TFC table is set according to a specific rule, In one rule (rule 1), clearance in write-in of data in respective temperature is made smaller than clearance in read-out of data. In the other one rule (rule 2), clearance in temperature at which tests are performed intensively is made smaller than clearance in the other test temperature. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a disk drive device and a design method thereof, and more particularly to heater control of a disk drive device including a heater that adjusts a clearance between a head element unit and a disk.

  As a disk drive device, a device using a disk of various modes such as an optical disk, a magneto-optical disk or a flexible magnetic disk is known. Among them, a hard disk drive (HDD) is used as a computer storage device. It has become widespread and has become one of the storage devices that are indispensable in current computer systems. Furthermore, the use of HDDs such as a removable memory used in a moving image recording / reproducing apparatus, a car navigation system, a mobile phone, a digital camera, etc. is expanding more and more due to its excellent characteristics.

  The magnetic disk used in the HDD has a plurality of data tracks formed concentrically, and each data track has a plurality of data including a plurality of servo data having address information and user data. A sector is recorded. A plurality of data sectors are recorded between each servo data. The head element part of the head slider supported by the oscillating actuator accesses the desired data sector according to the servo data address information, thereby writing data to the data sector and reading data from the data sector. It can be performed.

In order to improve the recording density of the magnetic disk, it is important to reduce the clearance between the head element portion that floats on the magnetic disk and the magnetic disk. For this reason, several mechanisms for adjusting the clearance have been proposed. One of them is provided with a heater in the head slider, and the clearance is adjusted by heating the head element portion with the heater. In this specification, this is called TFC (Thermal Flyheight Control). The TFC supplies a current to the heater to generate heat, and causes the head element portion to protrude by thermal expansion. As a result, the clearance between the magnetic disk and the head element portion is reduced. About TFC, it is disclosed by patent document 1, for example.
JP-A-5-20635

  In the clearance adjustment by TFC, it is ideal that the clearance is the same at each temperature in the operating temperature region. Similarly, it is ideal that the clearance is the same for both data writing and data reading. However, even if all the variation factors that are actually grasped are taken into account, the possibility that the minimum point of clearance occurs at a specific temperature in one of data writing and data reading due to unknown variation factors may be denied. Can not. On the other hand, in TFC, it is required to control the heater so as to avoid contact (head disk contact) between the head element part and the magnetic disk due to the protrusion of the head element part.

  One embodiment of the present invention includes a slider that floats on a rotating disk, a head element portion that is disposed on the slider, and a slider that is disposed on the slider so that the head element portion protrudes by thermal expansion. And a heater for adjusting the clearance of the disk drive device. This method performs an operation test of the disk drive device in each of a plurality of different temperature ranges. Further, in each of the operation tests in the plurality of different temperature ranges, the protrusion amount of the head element portion at the time of writing data is set to be larger than the protrusion amount at the time of reading data. By making the protrusion amount at the time of data writing larger than the protrusion amount at the time of data reading, the head disk contact can be detected more reliably. Details will be described later.

  The set value of the protrusion amount of the head element portion by the heater in the data read is preferably 90% or less of the write current in the data write and the protrusion amount set value by the heater. As a result, an appropriate margin can be obtained.

  According to another aspect of the present invention, there is provided a slider that floats on a rotating disk, a head element portion that is disposed on the slider, and a slider that is disposed on the slider so that the head element portion protrudes by thermal expansion. And a heater for adjusting a clearance between the disk drive device and the test method. This method performs an operation test of the disk drive device in each of a plurality of different temperature ranges. Furthermore, the protrusion amount of the head element portion at the time of data writing in the operation test with the longest test time is set to be larger than the protrusion amount at the time of data writing in the operation test in other temperature ranges. This makes it possible to easily verify the head disk contact.

  The temperature range of the operation test with the longest test time is preferably higher than the temperature range of other operation tests. Thus, an effective disk drive device test can be performed. Alternatively, in the operation test having the longest test time, it is preferable to set the protrusion amount of the head element portion at the time of data writing to be larger than the protrusion amount at the time of data reading. As a result, the head disk contact can be detected more reliably.

  In each of the operation tests in the plurality of different temperature ranges, it is preferable to set the protrusion amount of the head element portion at the time of data writing to be larger than the protrusion amount at the time of data reading. The protrusion amount setting value of the head element portion at the time of data writing in the operation test with the longest test time is 1 nm or more larger than the protrusion amount setting value of the head element portion at the time of data writing in the operation test in another temperature range. It is preferable. As a result, an appropriate margin can be obtained.

  A disk drive device according to another aspect of the present invention includes a slider that floats on a rotating disk, a head element portion disposed on the slider, and a slider disposed on the slider, the head element portion protruding by thermal expansion. Thus, at the same detection temperature of the heater, the temperature detector, and the temperature detector, the protrusion amount of the head element portion in data writing is the protrusion of the head element portion in data reading. And a controller for controlling the output to the heater so as to be larger than the amount.

  At the same detection temperature, the protrusion amount of the head element portion by the heater in the data reading is preferably 90% or less of the write current in the data writing and the protrusion amount by the heater.

  According to the present invention, it is possible to easily verify the head disk contact in the clear lath adjustment by TFC.

  Hereinafter, embodiments to which the present invention can be applied will be described. For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. Moreover, in each drawing, the same code | symbol is attached | subjected to the same element and the duplication description is abbreviate | omitted as needed for clarification of description. In the following, embodiments of the present invention will be described by taking a hard disk drive (HDD) as an example of a disk drive device as an example.

  FIG. 1 is a block diagram schematically showing the overall configuration of the HDD 1 according to the present embodiment. As shown in FIG. 1, an HDD 1 includes a sealed enclosure 10 and a magnetic disk 11, which is an example of a recording disk (recording medium), a head slider 12, an arm electronic circuit (AE: Arm Electronics) 13, a spindle disk. A motor (SPM) 14, a voice coil motor (VCM) 15, an actuator 16, and a temperature detector 19 are provided.

The HDD 1 further includes a circuit board 20 fixed to the outside of the enclosure 10. On the circuit board 20, each IC such as a read / write channel (RW channel) 21, a motor driver unit 22, a hard disk controller (HDC) and an MPU integrated circuit (hereinafter referred to as HDC / MPU) 23, and a RAM 24. It has. Each circuit configuration can be integrated into one IC, or can be divided into a plurality of ICs.
User data from the external host 51 is received by the HDC / MPU 23 and written to the magnetic disk 11 by the head slider 12 via the RW channel 21 and the AE 13. The user data stored in the magnetic disk 11 is read by the head slider 12, and the user data is output from the HDC / MPU 23 to the external host 51 via the AE 13 and the RW channel 21.

  The magnetic disk 11 is fixed to the SPM 14. The SPM 14 rotates the magnetic disk 11 at a predetermined angular velocity. The motor driver unit 22 drives the SPM 14 according to control data from the HDC / MPU 23. The magnetic disk 11 of this example has recording surfaces for recording data on both sides, and a head slider 12 corresponding to each recording surface is provided. Each head slider 12 includes a slider that floats on the magnetic disk, and a head element unit that is fixed to the slider and converts between a magnetic signal and an electric signal. The head slider 12 of this embodiment is provided with a heater for TFC that adjusts the clearance (flying height) between the head element portion and the magnetic disk 11 by heating. The structure of the head slider 12 will be described in detail later with reference to FIG.

  Each head slider 12 is fixed to the tip of the actuator 16. The actuator 16 is connected to the VCM 15, and moves in the radial direction on the magnetic disk 11 that rotates the head slider 12 by rotating about the rotation axis. The motor driver unit 22 drives the VCM 15 according to control data from the HDC / MPU 23. One or more magnetic disks 11 may be provided, and the recording surface can be formed on one side or both sides of the magnetic disk 11.

  The AE 13 selects one head element unit 122 that accesses the magnetic disk 11 from the plurality of head element units 122, and amplifies a reproduction signal reproduced by the selected head element unit 122 with a certain gain. To the RW channel 21. Further, the recording signal from the RW channel 21 is sent to the selected head element unit 122. The AE 13 further includes a heater driving circuit that supplies current (electric power) to the heater, and functions as an adjustment circuit that adjusts electric power (current / voltage) to the heater.

  In the read process, the RW channel 21 amplifies the read signal supplied from the AE 13 so as to have a constant amplitude, extracts data from the acquired read signal, and performs a decoding process. Data to be read out includes user data and servo data. The decoded read user data and servo data are supplied to the HDC / MPU 23. In the write process, the RW channel 21 code-modulates the write data supplied from the HDC / MPU 23, further converts the code-modulated write data into a write signal, and supplies the write signal to the AE 13.

  In the HDC / MPU 23, the MPU operates according to the microcode loaded in the RAM 24. As the HDD 1 starts up, the RAM 24 is loaded with data necessary for control and data processing from the magnetic disk 11 or ROM (not shown), in addition to the microcode operating on the MPU. The HDC / MPU 23 includes data such as read / write processing control, command execution order management, positioning control (servo control) of the head element unit 122 using servo signals, interface control, defect management, and ERP when an error occurs. Necessary processing related to the processing and overall control of the HDD 1 are executed. The HDC / MPU 23 executes TFC in the read / write process according to the temperature detected by the temperature detector 19.

  Next, the configuration of the TFC head slider 12 in this embodiment will be described. FIG. 2 is a cross-sectional view showing a partial configuration of the head slider 12 in the vicinity of the air outflow end surface (trailing side end surface) 121. The magnetic disk 11 rotates from left to right in FIG. The head slider 12 includes a head element unit 122 and a slider 123 that supports the head element unit 122. The TFC of this embodiment can be applied to both perpendicular magnetic recording and horizontal magnetic recording HDDs.

  The head element unit 122 reads and writes magnetic data from and to the magnetic disk 11. The head element unit 122 includes a read element 32 and a write element 31 on the trailing side. The write element 31 is an inductive element that generates a magnetic field between the magnetic poles 312 with a current flowing through the write coil 311 and records magnetic data on the magnetic disk 11. The read element 32 is a magnetoresistive element, and includes a magnetoresistive element 32 a having magnetic anisotropy, and the magnetic data recorded on the magnetic disk 11 by the resistance value that changes according to the magnetic field from the magnetic disk 11. read out.

  The head element portion 122 is formed on an AlTiC substrate constituting the slider 123 using a thin film forming process such as plating, sputtering, and polishing. The magnetoresistive element 32 a is sandwiched between magnetic shields 33 a and b, and the write coil 311 is surrounded by an insulating film 313. The head element portion 122 includes a protective film 34 such as alumina around the write element 31 and the read element 32, and the entire head element portion 122 is protected by the protective film 34. In the vicinity of the write element 31 and the read element 32, a heater 124 is formed by a thin film process using a thin film resistor. In this example, the heater 124 is located on the side of the head element portion 122 opposite to the diamagnetic disk 11. The heater 124 can be formed by meandering a thin film resistor using permalloy and filling the gap with alumina.

  When the AE 13 supplies a current to the heater 124 (when electric power is supplied), the vicinity of the head element portion 122 is projected and deformed by the heat of the heater 124. At the time of non-heating, the ABS surface of the head slider 12 has a shape indicated by S1, and a clearance that is a distance between the head element portion 122 and the magnetic disk is indicated by C1. The protruding shape S2 when the heater 124 is heated is schematically shown by a broken line in FIG. The head element unit 122 approaches the magnetic disk 11, and the clearance C2 at this time is smaller than the clearance C1. FIG. 2 is a conceptual diagram, and the dimensional relationship is not accurate. For example, the protruding surface shape S2 has a protruding amount of nanometer order (several nanometers).

  An HDD design method in this embodiment will be described. In particular, the TFC design in the HDD 1 will be described. The HDC / MPU 23 determines supply power (current / voltage) to the heater according to a preset TFC table (not shown). For example, the TFC table stores the output value to the heater at each temperature within the operating temperature range. The output value differs between data reading and data writing. The output value varies depending on the driving method of the heater 124, and is typically a current value or a power value.

  The HDC / MPU 23 sets the heater output indicated by the TFC table in the register of the AE 13 in accordance with the detected temperature detected by the temperature detector 19 and the read / write processing. The AE 13 outputs a current / voltage to the heater 124 according to the set value. Alternatively, the TFC table registers output values to the heater at several temperatures, and the HDC / MPU 23 uses the registered output at the registered temperature, and the output value between the registered temperatures is preset. Completion according to the formula.

  In the TFC design in the HDD 1, it is required to set an appropriate TFC table. In general, it is desirable that the clearance be constant over the entire operating temperature range. Similarly, it is desirable that the clearance be constant between data reading and data writing. Thereby, the smallest clearance can always be realized.

  Certainly, it would be ideal if such a TFC could be realized, but in the actual HDD 1, variations cannot be avoided. Even if all the variation factors grasped in the design are considered, there are always unknown variation factors. Therefore, the possibility that the minimum clearance point occurs at a specific temperature (singular condition) due to the factor cannot be denied. That is, if the clearance is minimized under certain conditions, head disk contact will occur.

  TFC adjusts the clearance by protruding the head element part 122. At the same time, the possibility of head disk contact increases, so it is necessary to set an appropriate TFC table to prevent this from happening. Is done. Therefore, in the HDD design of this embodiment, the TFC table is set according to a specific rule. One rule (rule 1) makes the clearance for data writing smaller than the clearance for data reading at each temperature.

  Another rule (Rule 2) makes the clearance at the temperature at which testing is intensively smaller than the clearance at other test temperatures. By designing the TFC table according to these rules, it is possible to easily verify that the desired clearance is maintained in the HDD development test.

  FIG. 3 shows an example of the protrusion amount (Clearance Loss) of the head element portion 122 when the TFC table is designed according to the design rule of this embodiment. In FIG. 3, the protrusion amount of the head element portion 122 on the inner peripheral side (ID) and the outer peripheral side (OD) is shown. In addition, the amount of protrusion at the time of data writing (WR) and data reading (RD) in each test temperature region (hereinafter also referred to as test temperature) of low temperature (LT), normal temperature (NT), and high temperature (HT) is shown. Yes. For example, the low temperature (LT) test temperature region is fixed at 10 ° C., the normal temperature (NT) test temperature region is fixed at 40 ° C., and the high temperature (HT) test temperature region is fixed at 70 ° C. This temperature corresponds to the temperature detected by the temperature detector 19 of the HDD 1. The test temperature region may vary within a predetermined width. Note that the high temperature test is typically performed at a drive temperature of 55-70 ° C.

  As shown in FIG. 3, at each test temperature (LT, NT, HT) on both the inner peripheral side (ID) and the outer peripheral side (OD), the protrusion amount (WR) in data writing is the protrusion amount (RD) in data reading. Bigger than). Further, the protrusion amount (WR) at the time of data writing at a high temperature (HT) is set larger than the protrusion amount at the time of data writing at other test temperatures (NT, LT).

  Here, the protruding amount of the head element portion 122 varies depending on several factors. In data reading (RD), the protrusion amount of the head element unit 122 is determined by two factors. One is the protrusion of the head element portion (dt-PTR) as the ambient temperature rises, and the other is the protrusion by the TFC using the heater 124 (R-TFC). For example, at a test temperature of normal temperature (NT) on the inner peripheral side (ID), the protrusion (dt-PTR) of the head element portion with an increase in the ambient temperature is 1.5 nm, and the protrusion due to TFC (R-TFC) is 1.8 nm. Further, in low-temperature (LT) data reading (RD), the protrusion (dt-PTR) of the head element portion as the ambient temperature increases is zero.

  On the other hand, in data writing (WR), the protrusion amount of the head element portion 122 is determined by three factors. One is the protrusion of the head element portion (dt-PTR) due to an increase in the environmental temperature, and the other is the protrusion of the head element portion (W-PTR) due to heat generation of the write element during data writing. One of them is protrusion by TFC (W-TFC) using the heater 124. For example, at a test temperature of normal temperature (NT) on the inner peripheral side (ID), the protrusion (dt-PTR) of the head element portion with an increase in ambient temperature is 1.5 nm, The protrusion (W-PTR) is 1.5 nm, and the protrusion due to TFC (W-TFC) is 0.5 nm.

  First, rule 1, that is, the clearance relationship between data writing and data reading will be described. In order to set the TFC table so as not to cause the head disk contact, it is necessary to accurately detect the head disk contact in the test in the design and development of the HDD 1.

  The HDD 1 incorporates various error recovery mechanisms in normal read processing. For this reason, even if the head disk contact actually occurs, it does not always manifest as an error in the HDD 1. That is, even if the HDD 1 cannot read the data correctly once by the head disk contact, the data can often be read correctly by the subsequent error recovery process.

  In the method of setting the TFC table by accumulating each parameter measurement data, when the same clearance is set for data writing and data reading, the clearance at the time of data reading is smaller due to unknown factors that cause clearance variations. There is a possibility. In this case, for the reason described above, although the head disk contact is actually generated, it does not become apparent, and there is a possibility that the head element portion 122 is deteriorated.

  On the other hand, in normal write processing, the HDD 1 typically does not verify the written data after writing data to the magnetic disk 11. Therefore, when a head disk contact occurs, the HDD 1 cannot accurately write data. By reading and checking the written data in the HDD 1 test, it is possible to reliably detect the occurrence of a head disk contact in the data writing test.

  As described above, in this embodiment, the HDD 1 is designed such that the clearance for data writing is smaller than the clearance for data reading. That is, the setting value of the protrusion amount of the head element unit 122 in data writing is larger than the setting value of the protrusion amount of the head element unit 122 in data reading. Therefore, head disk contact is more likely to occur in data writing than in data reading. For this reason, if head disk contact does not occur in data writing, it can be considered that clearance in data reading is also guaranteed. Further, in the data writing, the head disk contact can be detected more accurately than in the data reading.

  In this way, by setting the protrusion amount in data writing to be intentionally larger than that in data reading, the head disk contact can be detected easily and reliably, and a desired clearance is maintained in data writing and data reading. Can be easily verified. As a result, problems can be detected and improved in the development stage of the HDD 1.

  Here, a preferable difference amount between the protruding amount in data writing and the protruding amount in data reading will be described. As described repeatedly, there is variation in the protruding amount of the head element portion 122. It is necessary to set each protrusion amount with a specific margin so that the protrusion amount of the head element portion 122 in data writing is surely larger than the protrusion amount in data reading.

  Here, at each test temperature, the protrusion due to the ambient temperature is the same between data writing and data reading. On the other hand, there is a variation between the protrusion amount due to the write current and the protrusion amount due to the TFC. Therefore, it is important to determine the difference between the protrusion amount in data writing and the protrusion amount in data reading in consideration of these variations.

  According to the study by the inventors, the protrusion amount due to TFC (R-TFC) in data reading is the sum of the protrusion amount due to write current (W-PTR) and the protrusion amount due to TFC (W-TFC) ( W-PTR + W-TFC) is preferably 90% or less. That is, the difference between (W−PTR + W−TFC) and R−TFC is preferably 10% or more. Furthermore, the difference between (W−PTR + W−TFC) and R−TFC is more preferably 15% or more.

  FIG. 4 shows the amount of protrusion on the inner peripheral side (ID) at a test temperature of normal temperature (NT). Specifically, the graph on the left side of FIG. 4 shows the protrusion amount due to the write current (W-PTR) and the protrusion amount due to the TFC (W-TFC) in data writing (Write). The graph on the right side shows the protrusion amount (R-TFC) due to TFC in data reading (Read). As illustrated in FIG. 4, 90% of the sum (W−PTR + W−TFC) of the protrusion amount due to the write current (W−PTR) and the protrusion amount due to the TFC (W−TFC) in data writing, and further 85%. It is as follows.

  Next, rule 2 will be described in which the clearance at the temperature at which the operation test is intensively made smaller than the clearance at other test temperatures. As shown in FIG. 3, on the inner peripheral side (ID) and the outer peripheral side (OD), the protrusion amount of the data write (WR) at the high temperature (HT) is the data write at the low temperature (LT) and the normal temperature (NT) (NT). Larger than the amount of protrusion of (WR). In the example of FIG. 3, the protrusion amounts at the low temperature (LT) and the normal temperature (NT) are the same. Similarly, the protruding amount of data reading (RD) at high temperature (HT) is larger than the protruding amount of each data reading (RD) at low temperature (LT) and normal temperature (NT).

  In this embodiment, the operation test of the HDD 1 at a high temperature (HT) is the main operation test, and the total time is the longest. The test of the HDD 1 causes the HDD 1 to repeatedly perform a preset operation. Typically, operations that the HDD 1 can perform in a normal environment, such as writing and reading of a specific data pattern, and repetition of seek, are continuously executed. In particular, a long test called a long run test takes 2 to 6 weeks to test the HDD 1. In this embodiment, the long run test is performed only at high temperature (HT).

  Regarding the operation of the circuit elements on the control circuit board 20, the performance of the mechanical parts and the out-gas, etc., the high temperature is a severer temperature condition. Can improve the reliability.

  Here, the minimum point of the clearance in this embodiment is set at a high temperature (HT). At high temperature (HT), the HDD 1 is evaluated most intensively, so the operation test at this temperature can most reliably and accurately detect the head disk contact. Therefore, by setting the TFC table so that the clearance at high temperature (HT) is minimized, the clearance at other temperatures can be guaranteed. Thereby, it can be easily verified that a desired clearance is maintained at each temperature.

  FIG. 5 schematically shows the relationship between the temperature and the protrusion amount (Clearance loss) of the head element unit 122 according to the rules 1 and 2 of the present embodiment. FIG. 5 illustrates the temperature change of the protrusion amount in data writing and data reading without using the TFC, and the temperature change of the protrusion amount in data writing and data reading using the TFC. When TFC is used, the amount of protrusion in data writing is larger than that in data reading. Further, among the protrusion amounts at a low temperature of 10 ° C., a normal temperature of 40 ° C. and a high temperature of 70 ° C., the protrusion amount at a high temperature of 70 ° C. is the largest. In the figure, the amount of protrusion of data writing and data reading increases monotonously with temperature.

  Here, a preferable amount of difference between the amount of protrusion at a high temperature (HT) and the amount of protrusion at another temperature will be described. As described above, there is variation in the protruding amount of the head element portion 122. It is important to set each protrusion amount with a specific margin so that the protrusion amount of the head element portion 122 at high temperature (HT) is surely larger than the protrusion amount at other temperatures. According to the study by the inventors, the margin is preferably 1 nm or more. That is, after the high temperature (HT) clearance is first determined, the TFC value is set so that the clearance at normal temperature (NT) and low temperature (LT) is greater than the value obtained by subtracting 1 nm therefrom.

  Specifically, in FIG. 3, for data writing (WR) on the inner circumference side (ID), the difference between high temperature (HT) and normal temperature (NT) and low temperature (LT) is 1.0 nm, and data reading (RD) ), The difference between high temperature (HT) and normal temperature (NT) and low temperature (LT) is 1.0 nm and 1.2 nm. For data writing (WR) on the outer peripheral side (OD), the difference between high temperature (HT) and normal temperature (NT) and low temperature (LT) is 1.0 nm, and for data reading (RD), high temperature (HT) and normal temperature The difference between (NT) and low temperature (LT) is 1.1 nm and 1.2 nm.

  As mentioned above, although this invention was demonstrated taking preferable embodiment as an example, this invention is not limited to said embodiment. A person skilled in the art can easily change, add, and convert each element of the above-described embodiment within the scope of the present invention. For example, the above examples of TFC can be applied to disk drive devices other than HDDs.

  Further, as described above, it is preferable that both the rule 1 and the rule 2 are satisfied, but the HDD may be designed using only one of them. Further, when the protruding amount of writing at each temperature is larger than the protruding amount of reading, the protruding amount of writing at a high temperature may be higher than other temperatures. The protruding amount of reading does not have to follow the rule 2.

  In rule 1, it is preferable that the amount of protrusion in data writing is larger than the amount of protrusion in data reading at each test temperature (LT, NT, HT), but this relationship is the main test (HT in the above example). If this is satisfied, it does not have to be satisfied at other temperatures. The same applies to the clearance in each test temperature and read / write processing and the above-described margin.

  Further, by setting the largest amount of data write protrusion in the main test (HT in the above example), it is possible to effectively detect and verify the disk contact. At this time, the relationship between the protrusion amounts under other conditions may not follow the above-described rule 1 or rule 2.

In this embodiment, it is a block diagram which shows typically the whole structure of HDD. In this embodiment, it is sectional drawing which shows typically the structure of the head slider provided with the heater for TFC. An example of the protrusion amount (Clearance Loss) of the head element unit when the TFC table is designed according to the design rule of the present embodiment is shown. In the present embodiment, the protrusion amount on the inner peripheral side (ID) at the normal temperature (NT) test temperature is shown. In the present embodiment, the relationship between the temperature and the protrusion amount (Clearance loss) of the head element unit according to the rules 1 and 2 is schematically shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hard disk drive, 10 Enclosure, 11 Magnetic disk 12 Head slider, 14 Spindle motor, 15 Voice coil motor 16 Actuator, 19 Temperature detector, 20 Circuit board 21 Read / write channel, 22 Motor driver Unit 23 Hard disk controller / MPU, 24 RAM, 31 Write element 32 Read element, 32a Magnetoresistive element, 33a, b Shield, 34 Protective film 51 Host, 121 Trailing side end face, 122 Head element part, 123 Slider 124 Heater, 311 Write coil, 312 magnetic pole, 313 insulating film

Claims (9)

A slider that floats on a rotating disk, a head element portion disposed on the slider, and a heater that is disposed on the slider and adjusts a clearance from the disk by projecting the head element portion by thermal expansion. A method for testing a disk drive device having
In each of a plurality of different temperature ranges, perform an operation test of the disk drive device,
A method in which, in each of the operation tests in the plurality of different temperature ranges, the protruding amount of the head element portion at the time of writing data is set to be larger than the protruding amount at the time of reading data. The protrusion amount setting value of the head element portion by the heater in the data reading is 90% or less of the writing current in the data writing and the protrusion amount setting value by the heater.
The method of claim 1. A slider that floats on a rotating disk, a head element portion disposed on the slider, and a heater that is disposed on the slider and adjusts a clearance from the disk by projecting the head element portion by thermal expansion. A method for testing a disk drive device having
In each of a plurality of different temperature ranges, perform an operation test of the disk drive device,
A method of setting the protrusion amount of the head element portion at the time of data writing in the operation test with the longest test time to be larger than the protrusion amount at the time of data writing in the operation test in other temperature ranges The temperature range of the operation test with the longest test time is higher than the temperature range of the other operation test,
The method of claim 3. In the operation test with the longest test time, the protrusion amount of the head element unit at the time of data writing is set to be larger than the protrusion amount at the time of data reading.
The method of claim 3. In each of the operation tests in the plurality of different temperature ranges, the protrusion amount of the head element portion at the time of data writing is set to be larger than the protrusion amount at the time of data reading.
The method of claim 3. The protrusion amount setting value of the head element portion at the time of data writing in the operation test with the longest test time is 1 nm or more larger than the protrusion amount setting value of the head element portion at the time of data writing in the operation test in another temperature range. ,
The method of claim 3. A slider that floats on a rotating disk;
A head element portion disposed on the slider;
A heater that is disposed on the slider and adjusts a clearance between the disk by projecting the head element portion by thermal expansion;
A temperature detector;
A controller for controlling the output to the heater so that the protruding amount of the head element unit in data writing is larger than the protruding amount of the head element unit in data reading at the same detection temperature of the temperature detector;
A disk drive device comprising: At the same detection temperature, the protrusion amount of the head element portion by the heater in the data read is 90% or less of the write current in the data write and the protrusion amount by the heater.
The disk drive device according to claim 8.

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