JP2005346880A - Magnetic recording and reproducing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic recording and reproducing apparatus having high impact resistance and high environmental resistance and capable of being widely applied to a portable electronic device and a mobile communication device. <P>SOLUTION: The magnetic recording and reproducing apparatus is provided with a magnetic recording medium 16 using silicon as a substrate and having ≤50 mm diameter, a spindle motor 18 as a driving means supporting and rotating the magnetic recording medium 16, head suspension assemblies (32, 38, 47) including a magnetic head 40 performing recording and reproduction of a magnetic signal to the magnetic recording medium 16 and freely movably supporting the magnetic head 40 to the magnetic recording medium 16, a voice coil motor 24 performing positioning of the head suspension assembly and the like, a rectangular box-shaped casing 12 in which the spindle motor 18 and a printed circuit board controlling operation of the voice coil motor 24 are stored and whose upper surface is opened and a top cover closing an upper end opening part of the casing 12. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a magnetic recording / reproducing apparatus for recording / reproducing magnetic signals.

  In recent years, hard disk drives (HDDs), which are one type of magnetic recording / reproducing apparatus, have been remarkably improved in recording density, and even now mass-produced, the recording density has reached 80 Gbpsi (gigabit / square inch). . For this reason, it has become possible to realize high capacity even with a small HDD. For example, at 80 Gbpsi, a capacity of 6 GB can be realized with a 1-inch HDD.

  When a high recording capacity can be realized with a small diameter size of about 1 inch, it is expected to be widely applicable to portable applications such as mobile phones, portable music players, and PDAs. Products with 1-inch HDDs are already being sold in portable music players, and a certain market is being developed.

  As a magnetic recording medium used in a hard disk device, a structure in which a metal film is laminated on a substrate for a magnetic recording medium by a sputtering method has become mainstream. Aluminum substrates and glass substrates are widely used as substrates used for magnetic recording media. The aluminum substrate is obtained by forming a Ni-P alloy film on a mirror-polished Al-Mg alloy substrate to a thickness of about 10 m by electroless plating and further mirror-finishing the surface. There are two types of glass substrates, amorphous glass and crystallized glass. Both glass substrates are mirror-finished.

  In a magnetic recording medium for a hard disk device that is generally used at present, a nonmagnetic underlayer (Ni-Al alloy, Cr, Cr alloy, etc.), nonmagnetic intermediate layer on a glass substrate or an aluminum substrate. (Co—Cr, Co—Cr—Ta alloy, etc.), magnetic layer (Co—Cr—Pt—Ta, Co—Cr—Pt—B alloy, etc.), protective layer (carbon etc.) are sequentially formed. A lubricating film made of a liquid lubricant is formed thereon.

  By the way, as described above, a small HDD has a possibility of being applied to many portable electronic devices, mobile communication devices, and the like. Higher impact resistance and environmental resistance are required. However, HDDs that are widely used at present cannot be said to have sufficient impact resistance and environmental resistance, and stable characteristics that are widely used in such devices have not been obtained.

  The present invention has been proposed in view of the above, and an object thereof is to provide a magnetic recording / reproducing apparatus having high impact resistance and environmental resistance, which can be widely applied to portable electronic devices, mobile communication devices, and the like. Yes.

  (1) In order to achieve the above object, a first invention is a magnetic recording / reproducing apparatus, wherein a magnetic recording medium using silicon as a substrate and having a diameter of 50 mm or less, and supporting and rotating the magnetic recording medium A spindle motor as drive means, a magnetic head for recording and reproducing magnetic signals to and from the magnetic recording medium, a head suspension assembly for supporting the magnetic head movably with respect to the magnetic recording medium, and the head suspension A rectangular box-shaped housing having an upper surface in which a voice coil motor that rotates and positions the assembly, a printed circuit board that controls operations of the spindle motor and the voice coil motor, and an upper end of the housing are stored. And a top cover that closes the opening.

  (2) In the second invention, in addition to the configuration of the invention described in the above item (1), the thickness of the substrate of the magnetic recording medium is in a range of 0.6 mm to 0.25 mm. It is a feature.

  (3) In a third invention, in addition to the configuration of the invention described in the above item (1) or (2), the magnetic recording when the magnetic signal is not recorded or reproduced on the magnetic recording medium. The impact resistance of the medium is 2000 G or more.

  (4) In the fourth invention, in addition to the configuration of the invention described in any one of the above items (1) to (3), the magnetic signal is recorded on and reproduced from the magnetic recording medium. The magnetic recording medium is characterized in that the impact resistance is 300 G or more.

  (5) In the fifth aspect of the invention, in addition to the configuration of the invention described in any one of the above items (1) to (4), the rotational speed of the magnetic recording medium is 3600 times / minute or more. It is characterized by that.

  (6) In the sixth aspect of the invention, in addition to the configuration of the invention described in any one of the above items (1) to (5), the surface roughness (Ra) of the magnetic recording medium is 1. It is characterized by being in the range of 5-8 angstroms.

  In the magnetic recording / reproducing apparatus of the present invention, since silicon is used as the substrate of the magnetic recording medium, a magnetic recording medium with few surface defects and high impact resistance and environmental resistance can be obtained. And small size suitable for mobile communication devices.

  That is, since silicon having high rigidity is used for the substrate, the diameter of the magnetic recording medium can be reduced to 50 mm or less, and the apparatus can be miniaturized by reducing the diameter. It can be applied to devices and mobile communication devices.

  Further, since silicon having high rigidity is used for the substrate, the thickness of the substrate can be reduced, and the device can be further miniaturized.

  Moreover, the impact resistance at the time of non-writing and non-reading (at the time of non-recording and non-reproducing) is 2000 G or more, and the impact resistance at the time of writing and reading (at the time of recording and reproduction) is 300 G or more. Can be applied to electronic devices and mobile communication devices.

  Further, since silicon having high rigidity is used for the substrate, it can withstand rotation of 3600 times / min or more, and the magnetic recording / reproducing apparatus can be operated at higher speed.

  Furthermore, since the surface roughness (Ra) of the magnetic recording medium is in the range of 1.5 to 8 angstroms, more preferably in the range of 2 to 6 angstroms, the flying budget of the head medium can be improved, and at the time of drive design The margin can be enlarged.

  In the present invention, the magnetic recording / reproducing apparatus uses a magnetic recording medium using silicon as a substrate, and the diameter of the magnetic recording medium is 50 mm or less.

  As the silicon substrate, a high-purity single crystal substrate used for a semiconductor wafer can be used, but a substrate doped with impurities or a polycrystalline substrate can also be used. The silicon substrate can improve the surface smoothness compared to the glass substrate and Al substrate normally used as the substrate of the magnetic recording medium, and realize a very good surface property without surface defects or protrusions. Is possible. Further, the grains constituting the seed layer, the underlayer, and the magnetic layer formed thereon are epitaxially grown, so that the film quality is improved and the magnetic characteristics can be improved.

  When manufacturing a magnetic recording medium using a silicon substrate, it is possible to form a magnetic film on the silicon substrate as it is to make a magnetic recording medium, or to make a textured anisotropic medium. is there. Examples of the texture method include a method in which a mechanical texture is directly applied to a silicon substrate, a method in which a metal film such as NiP is formed by sputtering or plating and then a mechanical texture is applied, and a method in which a texture is applied after a surface treatment such as an oxide film is performed. it can. It is also possible to add anisotropy by oblique sputtering or the like. It is possible to control the surface roughness of the magnetic recording medium and control the flying characteristics (HDI) of the head by subjecting the surface to texture processing or etching.

  In the present invention, the diameter of the magnetic recording medium is 50 mm or less, more preferably 25 mm or less. Thus, by making the diameter of the magnetic recording medium small, the characteristic improvement of the magnetic recording / reproducing apparatus of the present invention becomes more remarkable. That is, compared to conventional magnetic recording media using glass substrates or aluminum substrates, surface smoothness and surface controllability are improved, and characteristics suitable for small-diameter HDDs can be easily obtained. The lower limit of the diameter of the magnetic recording medium is about 10 mm.

  In the present invention, the thickness of the substrate of the magnetic recording medium is preferably in the range of 0.6 mm to 0.25 mm, more preferably in the range of 0.35 mm to 0.25 mm. Since the substrate used in the magnetic recording / reproducing apparatus of the present invention has high rigidity, it is possible to make the substrate thinner, thereby further reducing the size of the magnetic recording / reproducing apparatus.

  The magnetic recording / reproducing apparatus of the present invention has the characteristics that the impact resistance at the time of non-writing and non-reading is 2000 G or more, and the impact resistance at the time of writing and reading is 300 G or more. Etc. can be applied.

  The magnetic recording medium used in the magnetic recording / reproducing apparatus of the present invention can withstand rotation of 3600 times / minute or more, and can provide a magnetic recording / reproducing apparatus capable of high-speed operation.

  The surface roughness (Ra) of the magnetic recording medium used in the magnetic recording / reproducing apparatus of the present invention is preferably in the range of 1.5 to 8 angstroms, more preferably 2 to 6 angstroms. By using a magnetic recording medium having such a surface roughness, the flying budget of the head medium can be improved, so that the margin for designing the drive can be increased.

  The characteristics of the magnetic recording / reproducing apparatus of the present invention are summarized as follows.

  (1) Since the silicon substrate has a high Vickers hardness, it has a non-operating impact characteristic (non-write, non-read impact characteristic) of about 100 G compared to a glass substrate generally used as a magnetic recording medium substrate of a small HDD. Can have a margin.

  (2) Since the silicon substrate has a high Vickers hardness, the glass substrate can have a margin of about 100 G even in operation impact characteristics (write and read impact characteristics).

  (3) Since the silicon substrate has a high Vickers hardness, it is possible to reduce the thickness of the magnetic recording medium. Even if the thickness is reduced by about 10%, the impact resistance equivalent to that of the glass substrate can be obtained.

  (4) Since the surface smoothness of the magnetic recording medium is improved as compared to the glass substrate, the flying budget of the head medium is improved, so that the margin when designing the drive can be expanded.

  (5) Since the surface smoothness of the magnetic recording medium is improved as compared with the glass substrate, the touch-down characteristic of the head is improved, and the environmental resistance of the HDD, in particular, the decompression characteristic is improved. Specifically, a characteristic improvement of about 0.1 atm can be obtained as compared with the case where a glass substrate is used.

  (6) Since the silicon substrate has conductivity, the media surface can be prevented from being charged by grounding the HDD, and the environmental resistance (ESD characteristics) is improved.

  (7) Since the rigidity of the substrate is increased, the magnetic recording medium is less likely to be deformed, the end of the magnetic recording medium is not in contact with other parts, and contamination (contamination, foreign matter, contaminants) inside the HDD is prevented. Decrease.

  (8) Since the rigidity of the substrate is increased, it can cope with high-speed rotation of the magnetic recording medium.

  Hereinafter, it will be described in detail with reference to the drawings.

  FIG. 1 is a plan view showing an HDD according to the present invention, and FIG. 2 is an enlarged side view showing a magnetic head portion.

  As shown in FIG. 1, the HDD includes a rectangular box-shaped case 12 having an upper surface opened and a top cover (not shown) that closes an upper end opening of the case screwed to the case with a plurality of screws.

  In the case 12, a magnetic disk 16 as a magnetic recording medium, a spindle motor 18 as a drive unit for supporting and rotating the magnetic disk 16, a plurality of magnetic heads 40 for writing and reading information on the magnetic disk 16, A carriage assembly 22 that supports these magnetic heads 40 so as to be movable with respect to the magnetic disk 16, a voice coil motor (hereinafter referred to as “VCM”) 24 that rotates and positions the carriage assembly 22, and the magnetic head 40 is used for the magnetic disk 16. When moved to the outermost periphery, a ramp load mechanism 25 that holds the magnetic head 40 away from the magnetic disk 16 and a substrate unit 21 having a read / write amplifier that is a recording / reproduction signal processing circuit are accommodated. ing.

  A printed circuit board (not shown) for controlling the operation of the spindle motor 18 and the VCM 24 is screwed to the outer surface of the bottom wall of the case 12 via the board unit 21.

  Each magnetic disk 16 has magnetic recording areas on the upper surface and the lower surface. The two magnetic disks 16 are fitted on the outer periphery of a hub (not shown) of the spindle motor 18 and are fixedly supported on the hub by a clamp spring 17. As a result, the two magnetic disks 16 are coaxially stacked with a predetermined gap. Then, by driving the spindle motor 18, the two magnetic disks 16 are integrally rotated in the arrow B direction at a predetermined speed.

  The carriage assembly 22 includes a bearing portion 26 fixed on the bottom wall of the case 12 and a plurality of arms 32 extending from the bearing portion. These arms 32 are positioned parallel to the surface of the magnetic disk 16 with a predetermined gap therebetween, and extend in the same direction from the bearing portion 26. The carriage assembly 22 includes an elongated plate-like suspension 38 that can be elastically deformed. The suspension 38 is configured by a leaf spring, and the base end thereof is fixed to the distal end of the arm 32 by spot welding or adhesion, and extends from the arm. Each suspension 38 may be formed integrally with the corresponding arm 32. The arm 32 and the suspension 38 constitute a head suspension, and the head suspension and the magnetic head 40 constitute a head suspension assembly.

  As shown in FIG. 2, each magnetic head 40 has a substantially rectangular slider 42 and a recording / reproducing head portion 44 formed on the end face of the slider 42, and is provided at the tip of the suspension 38. The gimbal spring 41 is fixed. Each magnetic head 40 is applied with a head load L directed toward the surface of the magnetic disk 16 due to the elasticity of the suspension 38. During operation, the flying height of the magnetic head 40 with respect to the magnetic disk 16 is set to 10.0 nm or less.

  As shown in FIG. 1, the carriage assembly 22 has a support frame 45 extending from the bearing portion 26 in the direction opposite to the arm 32, and the voice coil 47 constituting a part of the VCM 24 is supported by the support frame. Has been. The support frame 45 is integrally formed on the outer periphery of the voice coil 47 with synthetic resin. The voice coil 47 is positioned between a pair of yokes 49 fixed on the case 12, and constitutes the VCM 24 together with these yokes and a magnet (not shown) fixed to one of the yokes. When the voice coil 47 is energized, the carriage assembly 22 rotates around the bearing portion 26, and the magnetic head 40 is moved and positioned on a desired track of the magnetic disk 16.

  The ramp loading mechanism 25 includes a ramp 51 provided on the bottom wall of the case 12 and disposed outside the magnetic disk 16, and a tab 53 extending from the tip of each suspension 38. When the carriage assembly 22 rotates to the retracted position outside the magnetic disk 16, each tab 53 engages with the ramp surface formed on the ramp 51, and then is lifted by the ramp surface inclination, and the magnetic head 40. Unload the file.

  In the embodiment shown above, the substrate has a hole in the center and is inserted into the spindle motor, but a small hole is formed in the center, and is fixed directly to the top surface of the spindle motor with a screw through the hole. You can also Also, when using a substrate without holes, it is advantageous in that the recording area can be increased when the diameter is reduced, and it is possible to increase the rigidity compared to the substrate with holes, so that the impact resistance surface But it is effective. By joining the entire back surface of the substrate to the spindle motor, it is possible to prevent the substrate from being deformed and to further improve the impact resistance.

  (Example 1) A seed layer, a Cr alloy underlayer, a magnetic layer, and a C protective film were formed on each of a silicon substrate and a glass substrate processed to have an outer diameter of 21.6 mm, an inner diameter of 6 mm, and a thickness of 0.381 mm using a sputtering method. Was formed, and finally a lubricating film was applied to prepare a magnetic recording medium. The same film formation method and material were used for both substrates, but the magnetic properties were higher by about 500 [Oe] in Hc compared to the glass substrate when a silicon substrate was used. 1 Oe is 79 A / m.

  When the orientation of the base Cr and Co in the magnetic film was examined by X-ray analysis, it was found that the orientation of the silicon substrate was improved.

  When glide and roughness were measured with a glide measuring instrument and AFM, it was found that the silicon substrate was lower by about 1 nm for glide and about 2 angstroms for Ra. In order to investigate the flying characteristics of each magnetic recording medium, the touchdown (TD) characteristic / takeoff (TO) characteristic was measured using a head used in an actual drive. The TD characteristics showed a value lower by 1 nm or more for the silicon substrate, but it was found that the TO characteristics deteriorated by about 2 nm. This is because the surface is too smooth and the head is likely to be adsorbed, so that the TO characteristics are likely to deteriorate.

  (Example 2) A silicon substrate processed to a silicon substrate processed to an outer diameter of 21.6 mm, an inner diameter of 6 mm, and a thickness of 0.381 mm, and a substrate subjected to mechanical texture after NiP plating was applied to 100 nm. In the same manner as in Example 1, a seed layer, a Cr alloy underlayer, a magnetic layer, and a C protective film were formed by sputtering, and finally a lubricating film was applied to prepare a magnetic recording medium. As in the case of a normal glass substrate or Al substrate, it was confirmed that the magnetic film had anisotropy by applying texture, and the magnetic characteristics and electromagnetic conversion characteristics were improved. When the glide and roughness were measured, both were higher than those without the texture, so that the flying characteristics were improved and were equivalent to the glass substrate.

  (Example 3) The media of Example 1 and Example 2 were incorporated into an actual drive, and the error rate was measured at 3 burst. A drive composed of one side of a medium and one head is used, and the head is loaded / unloaded by a ramp load method. The rotational speed of the disk is 3600 rpm. Measurement was performed only at one location on the middle circumference. The higher the single electric characteristics, the higher the BER, but the number of defects was the smallest for the untextured silicon and the glass substrate was the largest.

  Example 4 A chamfer polish was applied to a silicon substrate processed to an outer diameter of 21.6 mm, an inner diameter of 6 mm, and a thickness of 0.381 mm, and film formation was performed in the same manner as in Example 1 to produce a magnetic recording medium. A magnetic recording medium using a chamfer polished substrate and a non-coated substrate was incorporated in the drive, and the impact test of the drive was performed using an impact tester. In both non-operational impact tests, the disk did not crack even when an impact of 2000 G was applied. In the operation impact test, all showed an impact resistance of 300 G or more, but a result of about 50 G was better when a substrate with chamfer polish was used.

It is a top view which shows HDD concerning this invention. It is a side view which expands and shows a magnetic head part.

Explanation of symbols

12 Case 16 Magnetic disk 17 Clamp spring 18 Spindle motor 21 Substrate unit 22 Carriage assembly 24 Voice coil motor (VCM)
25 Ramp load mechanism 26 Bearing portion 32 Arm 38 Suspension 40 Magnetic head 41 Gimbal spring 42 Slider 44 Head portion 45 Support frame 47 Voice coil 49 Yoke 51 Lamp 53 Tab

Claims (6)

A magnetic recording medium having a diameter of 50 mm or less using silicon as a substrate;
A spindle motor as drive means for supporting and rotating the magnetic recording medium;
A head suspension assembly including a magnetic head for recording and reproducing magnetic signals to and from the magnetic recording medium, and supporting the magnetic head movably with respect to the magnetic recording medium;
A voice coil motor for rotating and positioning the head suspension assembly;
A printed circuit board for controlling the operation of the spindle motor and the voice coil motor;
A rectangular box-shaped housing with an open top surface in which is stored,
A top cover for closing the upper end opening of the housing;
A magnetic recording / reproducing apparatus comprising:   The magnetic recording / reproducing apparatus according to claim 1, wherein a thickness of the substrate of the magnetic recording medium is in a range of 0.6 mm to 0.25 mm.   The magnetic recording / reproducing apparatus according to claim 1 or 2, wherein the magnetic recording medium has an impact resistance of 2000 G or more when recording and reproduction of magnetic signals on the magnetic recording medium are not performed.   4. The magnetic recording / reproducing apparatus according to claim 1, wherein the magnetic recording medium has an impact resistance of 300 G or more when recording and reproducing magnetic signals on the magnetic recording medium. 5.   The magnetic recording / reproducing apparatus according to claim 1, wherein the rotational speed of the magnetic recording medium is 3600 times / minute or more.   The magnetic recording / reproducing apparatus according to claim 1, wherein the magnetic recording medium has a surface roughness (Ra) in a range of 1.5 to 8 angstroms.

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