Source: http://www.google.com/patents/US7773323?dq=6981235
Timestamp: 2014-09-20 19:10:15
Document Index: 272718365

Matched Legal Cases: ['Application No. 2005', 'arts 40', 'arts 40', 'arts 40', 'arts 40', 'arts 40', 'arts 40', 'arts 40', 'arts 40']

Patent US7773323 - Magnetic recording medium, recording reproducing apparatus, and stamper - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign in<nobr>Advanced Patent Search</nobr>PatentsOn a magnetic recording medium, M sets of burst patterns are formed along a direction of rotation of a substrate in each burst pattern region. Each burst pattern is formed so as to include two types of burst signal units that have an equal length along a radial direction of the substrate. In a predetermined...http://www.google.com/patents/US7773323?utm_source=gb-gplus-sharePatent US7773323 - Magnetic recording medium, recording reproducing apparatus, and stamperAdvanced Patent SearchPublication numberUS7773323 B2Publication typeGrantApplication numberUS 12/412,600Publication dateAug 10, 2010Filing dateMar 27, 2009Priority dateFeb 16, 2005Fee statusPaidAlso published asCN1822094A, CN100429697C, US7532423, US20060198042, US20090185308Publication number12412600, 412600, US 7773323 B2, US 7773323B2, US-B2-7773323, US7773323 B2, US7773323B2InventorsAkimasa Kaizu, Yoshikazu Soeno, Makoto MoriyaOriginal AssigneeTdk CorporationExport CitationBiBTeX, EndNote, RefManPatent Citations (40), Non-Patent Citations (9), Classifications (14), Legal Events (1) External Links: USPTO, USPTO Assignment, EspacenetMagnetic recording medium, recording reproducing apparatus, and stamperUS 7773323 B2Abstract On a magnetic recording medium, M sets of burst patterns are formed along a direction of rotation of a substrate in each burst pattern region. Each burst pattern is formed so as to include two types of burst signal units that have an equal length along a radial direction of the substrate. In a predetermined range, (2M) centers in the radial direction of the burst patterns are present at intervals of (1/N) times the track pitch in the radial direction. The predetermined range has a length along the radial direction of (2M/N) times the track pitch. M or N is a natural number of 2 or higher. The two types of burst signal units are formed of non-recording regions and end regions of the burst signal units overlap in the radial direction in at least one part region of the substrate.
(1−M)�Tp/N+BW≦Wr≦(3�M−1)�Tp/N−BW where Wr is a reproducing head width of the magnetic head, BW is a length along the radial direction of the burst signal units, and Tp is the track pitch.
CROSS-REFERENCE TO RELATED APPLICATIONS This application is a divisional of U.S. patent application Ser. No. 11/353,933 filed on Feb. 15, 2006, which claims priority to Japanese Application No. 2005-039143, filed Feb. 16, 2005, the contents of which are expressly incorporated by reference in their entireties.
SUMMARY OF THE INVENTION However, by investigating the conventional magnetic disks 10 x 1, 10 x 2, the present inventors discovered the following problem. That is, to make present-day magnetic disks capable of high-density recording, it is necessary to increase the track density of data recording tracks. Accordingly, there is a tendency to reduce the length in the radial direction of the burst patterns (the servo patterns Ps1, Ps2, . . . described above), so that for magnetic recording media including the conventional magnetic disks 10 x 1, 10 x 2, the output signal outputted from a magnetic head when a burst pattern passes below the magnetic head tends to become weak. This means that for this type of magnetic recording media, there is a tendency for reduced sensitivity for a PES (Position Error Signal) as the recording density increases, which can make it difficult to carry out tracking servo control properly.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a magnetic recording medium and a recording/reproducing apparatus according to the present invention will now be described with reference to the attached drawings.
The above magnetic disk 10A is formed as described above so that both �M� and �N� for the present invention are �2�. Accordingly, if the values of �M=2� and �N=2� are substituted into a condition �(M+1)�Tp/N−BW≦Wr≦(M−1)�Tp/N+BW� to be satisfied by the magnetic recording medium according to the present invention, the magnetic disk 10A will satisfy the above condition so long as the width Wr of the reproducing element Ra of the magnetic head 3 is equal to or greater than a width Wr1 a (see FIG. 5) that is � 3/2 times the track pitch Tp minus the length L11� and equal to or less than a width Wr2 a (see FIG. 5) that is �� times the track pitch Tp plus the length L11�. In the present specification, the case where the width Wr of the reproducing element Ra of the magnetic head 3 is � 3/2 times the track pitch Tp minus the length L11� is described below as one example. Note that the width (the minimum width Wr1 a and the maximum width Wr2 a) of the reproducing element Ra of the magnetic head 3 when using the magnetic disk 10A will be described in detail later.
In addition, on the magnetic disks 10A, 10B described above, although the entire convex parts 40 a in the concave/convex patterns 40 from the protruding end parts (the surfaces of the magnetic disks 10A, 10B) to the base end parts thereof are formed of the magnetic layer 14 (magnetic material), the construction of the �recording regions� and the �non-recording regions� that construct the �pattern� for the present invention are not limited to this. More specifically, like a magnetic disk 10C shown in FIG. 20, for example, by forming a thin magnetic layer 14 so as to cover concave/convex patterns formed in the glass substrate 11 (concave/convex patterns where the concaves and convexes have the same positional relationship as the concave/convex patterns 40), it is possible to construct a concave/convex pattern 40 that corresponds to the �pattern� for the present invention from a plurality of convex parts 40 a (recording regions) whose surfaces are formed of magnetic material and a plurality of concave parts 40 b (non-recording regions) whose base surfaces are also formed of the magnetic material. Also, like a magnetic disk 10D shown in FIG. 21, it is possible to construct a concave/convex pattern 40 that corresponds to the �pattern� for the present invention where not only the convex parts 40 a (recording regions) but also the base parts of the concave parts 40 b (non-recording regions) are formed of the magnetic layer 14. As another example, although not shown, it is also possible to construct a concave/convex pattern 40 that corresponds to the �pattern� for the present invention so as to include convex parts 40 a (recording regions) where only the protruding end parts (the surface side of the magnetic recording medium: the upper end parts in FIG. 21) of the convex parts 40 a in the concave/convex pattern 40 are formed of the magnetic layer 14 and the base end parts of the convex parts 40 a are formed of a non-magnetic material, a soft magnetic material, and the like. In this way, when forming the recording regions and non-recording regions of the magnetic recording medium according to the present invention using concave/convex patterns, by forming at least the protruding end parts of the convex parts that construct the recording regions from a magnetic material, it is possible to sufficiently increase the ability to store a magnetic signal in a readable manner compared to the non-recording regions.
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computer-generated translation of JP 7-287950.5English language Abstract of JP 2004-110896.6English language Abstract of JP 3-225684.7English language Abstract of JP 5-282807.8English language Abstract of JP 7-287951.9English language Abstract of JP 8-339649.Classifications U.S. Classification360/48, 360/15, 360/77.02, 360/53, 360/77.08International ClassificationG11B5/09Cooperative ClassificationG11B5/59655, G11B5/743, G11B5/865, B82Y10/00European ClassificationB82Y10/00, G11B5/74A, G11B5/86B, G11B5/596F5Legal EventsDateCodeEventDescriptionJan 15, 2014FPAYFee paymentYear of fee payment: 4RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google