Stock material or miscellaneous articles – Composite – Of inorganic material
Reexamination Certificate
2002-01-22
2004-09-21
Jones, Deborah (Department: 1775)
Stock material or miscellaneous articles
Composite
Of inorganic material
C428S690000, C428S690000, C360S015000, C360S016000, C360S017000, C360S075000, C360S055000, C360S135000
Reexamination Certificate
active
06794062
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a magnetic master transfer medium provided with an uneven pattern for transferring data to a slave medium, and the usage method thereof.
2. Description of the Related Art
Generally speaking, with regard to magnetic storage mediums, those having a high storage capacity to record an increasing amount of data are desired. More preferably, so-called high-speed access mediums capable of advantageously reading out the data of a desired location in a short time are desired. One example of these mediums is the high density magnetic disk medium employed in hard disk or flexible disk apparatuses; so-called tracking servo technology, wherein the magnetic head accurately scans a narrow width track to achieve a high S/N ratio, plays a substantial role in realizing the high storage capacity thereof. A servo signal, address data signal, replay clock signal, etc., used for tracking within a certain interval occurring in one rotation of the disk are recorded in advance in a so-called preformatting, and the magnetic head is set so as to be capable of reading out the preformatted signals and correcting its position thereby, whereby the magnetic head can accurately scan the track.
In general, the servo signal (the servo pattern) is formed in the following order from the starting position of the servo frame: a preamble (a concurrent use signal), a gray code (the track number signal), and a burst signal (the signal determining the head position), and a data region follows thereafter. A portion of the burst signal is recorded at a distance displaced by ½ the width of the track from the center line of said track, and the remaining components of the servo signal are recorded on the center line of the track at an entire track pitch width. Further, the data region is narrower than the recording width of the servo signal, and a guard band portion is formed at the portions adjoining the inner and outer tracks thereto, which prevents the recording of a signal thereon.
At present, a preformat such as that described above employs a specialized servo recording apparatus, and is formed by writing the signal for one disk at a time, on one track at a time. The servo recording apparatus is provided with a magnetic head, which has a head width of, for example, 75% of the track pitch, and first rotates the disk one rotation with the magnetic head disposed adjacent to the disk; the pattern corresponding to the outer ½ track is written, after which the magnetic head is moved ½ track pitch inward and the pattern corresponding to the inner ½ track is written during the next rotation of the disc, whereby a one track portion of signal is written.
The servo recording apparatus described above is of high cost, and because a significant amount of time is required for the preformatting operation, this process accounts for the larger part of the manufacturing costs; reducing these costs is desirable.
In this regard, methods wherein the preformat data is transferred by a magnetic transfer, which is a method by which preformat data is not written one track at a time, has been proposed: for example, magnetic transfer technologies are introduced in Japanese Unexamined Patent Publication Nos. 10(1998)-269566, 10(1998)-40544, etc. According to the magnetic transfer of these methods: a master medium having an uneven pattern corresponding to the data to be transferred to the slave medium, which is a magnetic transfer medium such as a magnetic disk or the like, is prepared; this master medium is brought into a state of close contact with the slave medium; then, by applying a transfer magnetic field, the magnetic pattern corresponding to the data carried by the uneven pattern (e.g., a servo signal) of the master medium is transferred to the slave medium; the preformatting can be performed without changing the relative positions of the master medium and the slave medium, that is, while the two media remain stationary; and not only is it possible to perform an accurate recording of the preformat data, it becomes possible to do so in an extremely short time.
In order to improve the transfer quality of a magnetic transfer such as that described above, it is important that the master medium and the slave medium be disposed in close contact with each other in a manner wherein there is no gap therebetween. That is to say, if the two media are not properly brought into close contact with each other, regions in which the magnetic transfer is not effected occur, and signal omissions occur in the magnetic data transferred to a slave medium onto which the transfer has not been properly effected, producing a decrease in the signal quality thereof; for cases in which the recorded signal is a servo signal, a problem arises in that the tracking function is insufficient, resulting in a decrease in reliability.
To solve this problem, technologies have been proposed, in, see for example, Japanese Unexamined Patent Publication No. 11(1999)-161956, wherein the center portion of the master medium is formed as a curved protrusion, with respect to the slave medium, and when the master and slave mediums are brought into contact, the surface of the master medium deforms to become progressively flatter from the center portions thereof toward the periphery due to the pressure exerted thereon, and they are brought into close contact in a manner so that no air remains between two surfaces thereof, whereby the contact characteristics therebetween are improved.
However, in order to facilitate the transferal to the slave medium the same signal pattern servo written to the slave medium when the servo recording apparatus described above is employed, the uneven pattern formed on the master medium is formed by protrusions and depressions of a width equivalent to the track pitch (the track width) of the slave medium. More specifically, as shown in the partial perspective view of the form of the uneven pattern formed on the surface of the master medium illustrated in
FIG. 13
, the protrusion portion
71
, which has a width in the direction of the track pitch (direction Y) equivalent to the width of the track pitch P, is formed within one track or straddling two tracks.
Because these types of protrusion portions
71
are formed contiguously in the in the direction of the track (direction X) and in the direction of the track pitch (direction Y), as shown by the diagonal lines within
FIG. 13
, there are cases in which a depression portion
72
is formed surrounded on all four sides by protrusion portions
71
. If there are depression portions
72
of this type, that is, which are surrounded on four sides by protrusion portions
71
, even if a technology of the type proposed in the aforementioned Japanese Unexamined Patent Publication No. 11(1999)-161956 for improving the contact characteristics between the surface of the master medium and the surface of the slave medium is employed, in actuality, when the master medium and the slave medium are brought into close contact, the protrusion portions
71
surrounding the depression portion
72
end up being brought into close contact with the slave medium first and the air held in the thus closed off depression portion
72
is not removed, whereby a problem arises in that adequate contact characteristics cannot be obtained as a result of this air remaining within the space of the closed off depression portion
72
.
Further, because the magnetic transfer is performed in the state wherein the master and slave mediums have been brought into close contact as described above, cases occur in which the position determining of the master medium and the slave medium is performed while they are in the close contact state before the magnetic transfer is performed, and due to the friction generated by the rubbing together of the respective contact surfaces of the master medium and the slave medium during this position determining, the surface form of the pattern bearing the data of the master medium is worn away after repeated p
Nagao Makoto
Tsubata Hisashi
Blackwell-Rudasill G.
Fuji Photo Film Co. , Ltd.
Jones Deborah
Sughrue & Mion, PLLC
LandOfFree
Magnetic transfer master medium does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Magnetic transfer master medium, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Magnetic transfer master medium will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3267444