Magnetic recording and playback device

Abstract

To provide a magnetic recording and reproducing device capable of preventing changes in the amount of slider floating due to changes in the amount of oxygen in the device.SOLUTION: A magnetic recording and reproducing device 1 includes a magnetic recording medium 2 having a protective layer, a magnetic head 10 having a heat-assisted element, and an oxygen amount detection unit 180 for detecting the oxygen amount. Oxygen and helium are sealed in the magnetic recording and reproducing device 1 as the atmosphere inside the device.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Embodiments of the present invention relate to a magnetic recording and reproducing apparatus.

Background Art

[0002] As a magnetic recording and reproducing apparatus, for example, there is a hard disk drive (HDD). As one of the recording methods of HDD, there is a heat assisted magnetic recording method (HAMR). In HAMR, there is a mode in which materials such as a protective layer and a lubricating layer in the HDD are decomposed by heat or light, carbon is released into the atmosphere in the apparatus, and is collected at the tip of the near-field light element, resulting in failure. On the other hand, it has been proposed to put oxygen into the HDD to burn carbon. However, when oxygen is introduced into a drive sealed with He or the like, there is a problem that oxygen is consumed not only for the purpose of protecting HAMR. Therefore, it is required to set the initial oxygen concentration so that a certain amount of oxygen remains in the drive even as time passes in accordance with oxygen consumption. On the other hand, when oxygen is consumed over time and the pressure inside the apparatus decreases, there is also a problem that the floating amount of the slider changes and an HDD (head disk interface) failure occurs.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An embodiment of the present invention aims to obtain a magnetic recording and reproducing apparatus capable of suppressing a change in the floating amount of a slider accompanying a change in the amount of oxygen in the apparatus.

Means for Solving the Problems

[0005] According to the embodiment, a magnetic recording medium having a protective layer, A magnetic head having a heat assist element, Detects oxygen levels Oxygen quantity Including a detection unit, Magnetic recording and playback device with oxygen and helium sealed inside. In, The oxygen quantity detection unit further includes an oxygen quantity prediction unit that predicts the oxygen quantity based on the bit error rate in a magnetic recording and regeneration apparatus. It will be provided. [Brief explanation of the drawing]

[0006] [Figure 1] This is a block diagram showing an example of the control configuration of a magnetic recording and playback apparatus according to an embodiment. [Figure 2] This is a block diagram showing another example of the control configuration of the magnetic recording and playback device according to the embodiment. [Figure 3] This graph illustrates an example of the decrease in head levitation over time. [Figure 4] This is a flowchart illustrating an example of the operation of the oxygen level monitor in a magnetic recording and playback device according to the embodiment. [Figure 5] This is a block diagram showing another example of the control configuration of the magnetic recording and playback device according to the embodiment. [Figure 6] This is a partial cross-sectional view of a magnetic recording and playback device according to an embodiment. [Figure 7] This is a flowchart illustrating an example of the operation of the oxygen level monitor in a magnetic recording and playback device according to the embodiment. [Figure 8] This is a block diagram showing a modified version of Figure 5. [Figure 9] This is a graph showing the change in BER. [Figure 10] This is a block diagram showing another example of the control configuration of the magnetic recording and playback device according to the embodiment. [Figure 11] This is a flowchart illustrating an example of the operation of the oxygen level monitor in a magnetic recording and playback device according to the embodiment. [Modes for carrying out the invention]

[0007] The magnetic recording and playback apparatus according to this embodiment includes a magnetic recording medium having a protective layer, a magnetic head having a heat-assisted element, and a detection unit for detecting the amount of oxygen, and is sealed with oxygen and helium (He).

[0008] According to this embodiment, by detecting the amount of oxygen using the detection unit, it becomes possible to adjust the magnetic recording and playback device in response to changes in the amount of oxygen in the atmosphere inside the device.

[0009] The protective layer may include a lubricating layer consisting of a lubricant provided on the protective layer. Furthermore, the oxygen quantity detection unit may include, for example, an oxygen meter, or an oxygen quantity prediction unit that predicts the amount of oxygen based on the bit error rate. Furthermore, the oxygen level can be set to 1-20% by volume of the instrument's atmosphere. Within this range, long-term reliability of the instrument, such as 5 years, tends to be ensured. Outside this range, ensuring long-term reliability tends to become difficult.

[0010] The embodiments will be described below with reference to the drawings. Furthermore, the disclosure is merely an example, and any modifications that can be easily conceived by a person skilled in the art while maintaining the spirit of the invention are naturally included within the scope of the present invention. In addition, the drawings may schematically represent the width, thickness, shape, etc. of each part in order to clarify the explanation, but these are merely examples and do not limit the interpretation of the present invention. In addition, in this specification and each drawing, elements similar to those described above in previously shown drawings are denoted by the same reference numerals, and detailed explanations may be omitted as appropriate.

[0011] (Example 1) First, let's describe Example 1. Figure 1 is a block diagram showing an example of the control configuration of the first magnetic recording and playback apparatus according to the embodiment. As shown in FIG. 1, the first magnetic recording and reproducing apparatus 1 includes a magnetic disk 2 as a magnetic recording medium, a spindle motor (SPM) 3 as a rotational driving unit, an actuator assembly 4, a voice coil motor (VCM) 5, and a magnetic head 10. The magnetic disk 2 is provided with a management area 2a for recording information for managing the data to be recorded. Further, oxygen and He are enclosed in the first magnetic recording and reproducing apparatus 1 as the internal atmosphere of the apparatus.

[0012] Furthermore, the first magnetic recording and reproducing apparatus 1 includes a head amplifier IC 110, an R / W channel 120, a hard disk controller (HDC) 130, a microprocessor (MPU) 140, a driver IC 150, and a memory 160. Also, the first magnetic recording and reproducing apparatus 1 can be connected to a host computer (host) 170. Note that the R / W channel 120, the HDC 130, and the MPU 140 may be incorporated in a single-chip integrated circuit.

[0013] The magnetic head 10 includes a write head 10W, a read head 10R, and an assist unit 100 including an assist element. The write head 10W writes data to the magnetic disk 2. The read head 10R reads data from the magnetic disk 2. The assist unit 100 assists in writing data when the write head 10W writes data to the magnetic disk 2. The heater HE adjusts the flying height of the write head 10W or the read head 10R with respect to the disk surface of the magnetic disk 1. The magnetic head 10 can include a single or a plurality of magnetic heads. The assist element is a near-field light element as a thermal assist element, and further includes a laser light source that outputs laser light to the near-field light element. Examples of the assist power applied to the assist element include laser power, such as the current applied to the laser light source.

[0014] The spindle motor 3 is driven by a drive current (or drive voltage) supplied from the driver IC 150. The data pattern is recorded and reproduced on the magnetic disk 2 by the magnetic head 10. The voice coil motor 5 operates the voice coil, and by rotating the actuator assembly 4 from the unload position of a lamp load mechanism (not shown), the magnetic head 10 is moved onto a desired track of the magnetic disk 2 and positioned at a predetermined position on the magnetic disk 2. The voice coil motor 5 is driven by a drive current (or drive voltage) supplied from the driver IC 150.

[0015] The head amplifier IC 110 supplies a write signal (write current) corresponding to the write data supplied from the R / W channel 120 to the write head 10W. Also, it controls the optical output output from the thermal assist unit 100. Further, the head amplifier IC 110 amplifies the read signal output from the read head 10R and transmits it to the R / W channel 120. Furthermore, the head amplifier IC 110 adjusts the voltage applied to the heater HE to adjust the flying height of the write head 10W or the read head 10R with respect to the disk surface of the magnetic disk 1.

[0016] The R / W channel 120 is a signal processing circuit that processes signals related to reading (read) / writing (write). The R / W channel 120 includes a read channel that executes signal processing of read data and a write channel that executes signal processing of write data. The read channel converts the read signal into digital data and demodulates the read data from the digital data. The write channel encodes the write data transferred from the HDC 130 and transfers the encoded write data to the head amplifier IC 110.

[0017] The HDC130 controls the writing of data to the magnetic disk 2 and the reading of data from the magnetic disk 2 via the magnetic head 10, head amplifier IC 110, R / W channel 120, and MPU 140. The HDC130 forms an interface between the first magnetic recording and playback device 1 and the host 170 and performs read data and write data transfer control. In other words, the HDC130 functions as a host interface controller that receives signals transferred from the host 170 and transfers signals to the host 170. The HDC130 also receives commands (write commands, read commands, etc.) transferred from the host 170 and transmits the received commands to the MPU 140.

[0018] The oxygen detection unit 180 can be installed at any position within the device and includes, for example, an oxygen meter for measuring oxygen, or a function for indirectly predicting the amount of oxygen. It can detect the amount of oxygen in the atmosphere inside the first magnetic recording and playback device 1 at the time the oxygen amount needs to be checked. The detection result is transmitted to the MPU 140.

[0019] The MPU140 is the main controller (control unit) of the first magnetic recording and playback device 1, and performs servo control necessary for controlling read / write operations and positioning the magnetic head 10. It controls the head amplifier IC110 according to the oxygen level detection result from the oxygen detection unit 180, and can adjust the first magnetic recording and playback device 1 in response to changes in the oxygen level, for example, by adjusting the levitation amount or assist power of the magnetic head 10.

[0020] The driver IC 150 controls the drive of the spindle motor 3 and the voice coil motor 5 according to the control of the MPU 140. When the voice coil motor 5 is driven, the magnetic head 10 is positioned on the target track on the magnetic disk 2. Memory 160 includes volatile memory and non-volatile memory. For example, memory 160 includes a buffer memory consisting of DRAM and flash memory. The first magnetic recording and reproducing apparatus according to this embodiment is sealed with oxygen and helium.

[0021] Figure 2 shows a graph illustrating an example of oxygen consumption over elapsed time in the first magnetic recording and playback device. Figure 101 shows a graph illustrating the relationship between the elapsed time and the remaining oxygen in the first magnetic recording and playback device. As shown in the figure, when He or the like is sealed inside the first magnetic recording and playback device and oxygen is added, the oxygen is consumed over time. In addition to burning the carbon generated on the surface of the heat-assisted element, oxygen can also be consumed for oxidation reactions of substances inside the device. Therefore, when sealing in oxygen, it is desirable to adjust the initial oxygen concentration so that a certain amount of oxygen remains in the drive even after time has passed, according to the oxygen consumption of each first magnetic recording and playback device.

[0022] Figure 3 shows a graph illustrating an example of how the amount of head rise changes in response to a decrease in atmospheric pressure over time. Figure 102 shows a graph illustrating the relationship between atmospheric pressure and head levitation. As illustrated, as oxygen in the device is consumed over time and the pressure inside the device decreases, the head levitation decreases, which can lead to HDI failures such as head crashes, or the distance between the heat assist element and the recording surface decreases, causing the medium to be excessively heated by the heat assist element. Therefore, the first magnetic recording and playback device can be adjusted according to the amount of oxygen in the atmosphere inside the first magnetic recording and playback device by increasing the levitation or decreasing the assist power. On the other hand, when the pressure inside the device decreases, the head levitation may increase. In this case, the head and the recording surface separate, which can lead to insufficient magnetic recording quality or inadequate heating of the medium by the heat assist element. Whether the levitation decreases or increases depends on the configuration of the first magnetic recording and playback device. Therefore, the first magnetic recording and playback device can be adjusted according to the amount of oxygen in the atmosphere inside the first magnetic recording and playback device by decreasing the levitation or increasing the assist power. Thus, according to this embodiment, in a heat-assisted magnetic recording and playback device with oxygen sealed inside, the amount of oxygen can be detected by the oxygen amount detection unit, thereby adjusting the levitation amount or the assist power applied to the heat-assisted element according to the amount of oxygen.

[0023] Figure 4 shows a flowchart illustrating an example of the operation of the oxygen level monitor in the first magnetic recording and playback apparatus according to this embodiment. First, it is determined whether it is time to check the oxygen level (ST1). If the answer is No, the oxygen level detection is terminated. If the answer is Yes, the oxygen level detection unit 180 performs periodic oxygen level detection (ST2). The timing for monitoring the oxygen level can be, for example, at regular intervals such as every day, or when a command is received from the host 170.

[0024] Next, it is determined whether the oxygen level has changed (ST3). If the result is No, the detection of the oxygen level is terminated. If the result is Yes, the first magnetic recording and playback device can be adjusted (ST4) to maintain a constant recording quality that varies depending on the oxygen level, for example, by adjusting the head levitation amount or assist power. Here, the amount of head levitation amount or assist power to be changed according to the change in oxygen level can be confirmed in advance during the factory inspection. Alternatively, a table can be created from the average values ​​of multiple first magnetic recording and playback devices, and adjustments can be made according to that table.

[0025] (Example 2) Next, Example 2 will be described. Figure 5 shows a block diagram representing an example of the control configuration of the second magnetic recording and playback device according to the embodiment. The second magnetic recording and playback device 1-1 can have the same control configuration as the first magnetic recording and playback device 1 in Figure 1, except that it uses an MPU 140-1 instead of an MPU 140, and uses a memory 160-1 that includes a storage unit 161 for storing the head levitation amount, assist power amount, or a table thereof according to the oxygen change, instead of a memory 160. The MPU140-1 includes a float amount control unit 145 that controls the head amplifier IC 110 according to the oxygen amount detection result received from the oxygen amount detection unit 180, and can adjust the float amount of the head 10 by changing the voltage applied to the heater HE. The second magnetic recording and playback apparatus according to the embodiment is sealed with oxygen and helium.

[0026] Figure 6 is a cross-sectional view of the light head 10W and magnetic disk 2, which are part of the magnetic recording and reproducing apparatus of Embodiment 1 relating to the first and second magnetic recording and reproducing apparatuses. The magnetic disk 2 comprises a substrate 20 and, sequentially stacked on the substrate 20, a heat sink layer 21, a crystal orientation layer 22, a vertical recording layer 23, and a protective layer 24. The vertical recording layer 23 has a large anisotropy perpendicular to the disk surface. The crystal orientation layer 22 is positioned below the vertical recording layer 23 to improve its orientation. The heat sink layer 21 is positioned below the crystal orientation layer 22 to suppress the spread of the heating area. The protective layer 24 is positioned above the vertical recording layer 23 to protect it and includes a lubricating layer (not shown) on its surface, to which a lubricant is applied.

[0027] The magnetic head 10 is a separate magnetic head in which the recording head 10W and the playback head 10R are separated. The recording head 10W consists of a main magnetic pole 40 made of a high-permeability material that generates a magnetic field perpendicular to the disk surface, a trailing yoke 50 magnetically connected to the main magnetic pole 40 that conducts magnetic flux through the main magnetic pole 40, a return shield magnetic pole 60 located on the reading side of the main magnetic pole 40 to efficiently close the magnetic path directly beneath the main magnetic pole, a coil 70 arranged to wrap around the magnetic path including the trailing yoke and the return shield magnetic pole to conduct magnetic flux through the main magnetic pole 40, a heater 80 as an example of a heater HE for controlling the amount of levitation of the recording head, a near-field optical element 30 located on the reading side of the main magnetic pole 40 that generates near-field light to heat the vertical recording layer 23 of the magnetic recording medium 2, and a waveguide 31 for propagating the light for generating near-field light. The light source is a laser diode 32 mounted on the slider of the actuator assembly 4. As the near-field optical element 30, for example, an alloy consisting of Au, Pd, Pt, Rh, or Ir, or several combinations thereof, can be used. As an insulating layer (not shown) provided between the main magnetic pole 40 and the near-field optical element 30, for example, an oxide consisting of SiO2, Al2O3, etc., can be used. The protective layer 24 and its lubricant material tend to decompose due to heat and light, releasing carbon that adheres to, for example, the near-field optical element 30, but can be burned off by the oxygen sealed inside the device.

[0028] Figure 7 shows a flowchart illustrating an example of the operation of the oxygen level monitor in the second magnetic recording and playback apparatus according to this embodiment. To operate the oxygen level monitor, the MPU 140 first determines whether it is time to detect the oxygen level (ST11). If the answer is No, it terminates the oxygen level detection. If the answer is Yes, the oxygen level detection unit 180 performs periodic oxygen level detection (ST12). The timing for monitoring the oxygen level can be, for example, at regular intervals such as every day, or when a command is received from the host 170.

[0029] Next, the MPU 140 determines whether the oxygen level has changed based on the oxygen level detection result received from the oxygen level detection unit 180 (ST13). If the result is No, the oxygen level detection is terminated. If the result is Yes, the levitation control unit 145 can control, for example, the head amplifier IC 110 to change the voltage applied to the heater HE and adjust the levitation amount of the magnetic head 10 (ST14). Here, the data of the applied voltage of the heater HE according to the change in oxygen level can be confirmed in advance during the factory inspection and stored in the storage unit 161. The change in oxygen level makes it possible to check the pressure reduction inside the second magnetic recording and playback device 1-1 and the change in the levitation amount of the magnetic head 10, for example, a decrease in the levitation amount. Alternatively, the applied voltage of the heater HE can be compiled into a table from the average value of multiple second magnetic recording and playback devices and stored in the storage unit 161. When the oxygen level changes, the levitation amount of the magnetic head 10 can be adjusted according to the data or table obtained from the storage unit 161.

[0030] Thus, in the second magnetic recording and playback device 1-1 according to this embodiment, in addition to the configuration of the first magnetic recording and playback device 1, a levitation amount control unit 145 for controlling the levitation amount of the magnetic head 10 can be further provided. By using the levitation amount control unit 145, when the levitation amount of the magnetic head 10 changes due to a change in the amount of oxygen in the atmosphere inside the device, the levitation amount of the magnetic head 10 can be controlled, making it possible to adjust the second magnetic recording and playback device 1-1 in response to the change in the amount of oxygen in the atmosphere inside the device 1-1. Furthermore, the oxygen level detection unit 180 can be equipped with a function to indirectly predict the oxygen level.

[0031] Here, we will describe a modified example of Example 2. Figure 8 shows a block diagram representing the modified example of Figure 5. As shown in the figure, the third magnetic recording and playback device 1-2 can have the same control configuration as the second magnetic recording and playback device 1-1 in Figure 5, except that it includes an oxygen quantity prediction unit 181 that indirectly predicts the amount of oxygen instead of an oxygen quantity detection unit 180, an oxygen quantity detection unit 180-1, and a BER measurement unit 190 connected to the oxygen quantity prediction unit 181 and the MPU 140-1 to measure the bit error rate (BER). The oxygen quantity prediction unit 181 has a function to detect changes in the oxygen quantity. In this function, an electrical characteristic measurement area is set up in a predetermined area on the medium 2, the electrical characteristics of BER are measured in that area, and the change in oxygen quantity can be predicted based on the change in BER from the initial value at the time of shipment.

[0032] Figure 9 shows a graph representing the change in BER in relation to the change in buoyancy, which was determined in advance during the pre-shipment inspection. Figure 103 shows a graph representing the relationship between the ascent amount and BET. By maintaining a graph like Figure 9, the BER can be measured at the timing when the oxygen amount is detected periodically, and the ascent change and oxygen change can be predicted from the change in BER. The applied voltage of the heater HE can be changed from the change in the oxygen amount from the initial value. Here, characteristics such as SN or signal output can be used instead of BER.

[0033] (Example 3) Next, Example 3 will be described. Figure 10 shows a block diagram representing an example of the control configuration of the fourth magnetic recording and playback apparatus according to the embodiment. The fourth magnetic recording and playback device 1-3 can have the same control configuration as the first magnetic recording and playback device 1 in Figure 1, except that it uses an MPU 140-3 instead of an MPU 140, and uses a memory 160-1 that includes a storage unit 161 for storing the head levitation amount, assist power amount, or a table thereof according to the oxygen change, instead of a memory 160. The MPU140-3 includes an assist power control unit 143 for performing thermal-assisted recording by applying assist power to a thermal assist element. The assist power control unit 143 can control the head amplifier IC 110 according to the oxygen level detection result received from the oxygen level detection unit 180, and change the assist power applied to the thermal assist element to perform thermal-assisted recording. The fourth magnetic recording and reproducing apparatus according to the embodiment is sealed with oxygen and helium.

[0034] Figure 11 shows a flowchart illustrating an example of the operation of the oxygen level monitor in the fourth magnetic recording and playback apparatus according to this embodiment. To operate the oxygen level monitor, the MPU140-3 first determines whether it is time to check the oxygen level (ST21). If the answer is No, it terminates the oxygen level check. If the answer is Yes, the oxygen level detection unit 180 periodically detects the oxygen level (ST22). The timing for monitoring the oxygen level can be, for example, at regular intervals such as every day, or when a command is received from the host 170.

[0035] Next, the MPU 140-3 determines whether the oxygen level has changed based on the oxygen level detection result received from the oxygen level detection unit 180 (ST23). If the result is No, the oxygen level detection is terminated. If the result is Yes, the assist power control unit 143 can control, for example, the head amplifier IC 110 to change the voltage applied to the assist element 30 and adjust the assist power (ST24). Here, the assist element 30 is a near-field optical element as a thermal assist element, and further includes a laser light source 32 that outputs laser light to the near-field optical element. The assist power control unit 143 can control the laser power, for example, the current applied to the laser light source 32. Laser power data corresponding to the change in oxygen level can be confirmed in advance during the factory inspection and stored in the storage unit 161. Alternatively, the laser power can be compiled into a table from the average value of multiple 4th magnetic recording and playback devices and stored in the storage unit 161. When the oxygen level changes, the laser power can be adjusted according to the data or table obtained from the storage unit 161.

[0036] Thus, in the fourth magnetic recording and playback apparatus according to this embodiment, in addition to the configuration of the first magnetic recording and playback apparatus, an assist power control unit 143 for controlling the assist power supplied to the heat assist element 30 can be further provided. By using the assist power control unit 143, even if the amount of levitation of the magnetic head 10 changes due to a change in the amount of oxygen in the atmosphere inside the apparatus 1-3, and the heat assist effect of the heat assist element 30 changes, it becomes possible to adjust the fourth magnetic recording and playback apparatus 1-3 in response to the change in the amount of oxygen in the atmosphere inside the apparatus.

[0037] Furthermore, the oxygen quantity detection unit 180 can be equipped with a function to indirectly predict the amount of oxygen. For example, similar to the third magnetic recording and playback device 1-2 shown in Figure 8, instead of the oxygen quantity detection unit 180, an oxygen quantity detection unit 180-1 can be provided which has an oxygen quantity prediction unit 181 that indirectly predicts the amount of oxygen. In addition, a BER measurement unit 190 can be further provided which is connected to the oxygen quantity prediction unit 181 and the MPU 140-1 to measure the bit error rate (BER).

[0038] The oxygen quantity prediction unit 181 has a function to detect changes in the oxygen quantity. This function involves setting up an electrical characteristic measurement area in a pre-defined region on the medium 2, measuring the electrical characteristics of the BER in that area, and predicting the change in oxygen quantity based on the change in BER from the initial value at the time of shipment. For example, by measuring the BER at the timing of periodic oxygen quantity detection, the change in buoyancy and the change in oxygen quantity can be predicted from the change in BER. The laser power can be changed based on the change in oxygen quantity from the initial value. Here, characteristics such as SN or signal output can be used instead of BER.

[0039] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0040] 1, 1-1, 1-2, 1-3…Magnetic recording and playback device, 2…Magnetic recording medium, 3…Rotation drive unit, 10, 10W, 10R…Magnetic head, 30,…Near-field optical element, 32…Laser light source, 140, 140-1, 140-3…MPU, 143…Assist power control unit, 145…Levitation amount control unit, 161…Storage unit

Claims

1. A magnetic recording medium having a protective layer, A magnetic head having a heat assist element, It includes an oxygen level detection unit that detects the amount of oxygen, In a magnetic recording and playback device filled with oxygen and helium, The oxygen quantity detection unit further includes an oxygen quantity prediction unit that predicts the oxygen quantity based on the bit error rate, in a magnetic recording and playback apparatus.

2. The magnetic recording and playback apparatus according to claim 1, further comprising a levitation amount control unit for controlling the levitation amount of the magnetic head.

3. The magnetic recording and regeneration apparatus according to claim 1, further comprising an assist power control unit for applying assist power to the heat assist element to perform heat-assisted recording.

4. The magnetic recording and regeneration apparatus according to claim 1, wherein the amount of oxygen is 1 to 20% by volume of the apparatus atmosphere.

Images