Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
2001-05-01
2004-04-06
Vo, Peter (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S592100, C029S602100, C029S856000, C029S858000, C264S319000, C264S320000, C264S322000, C427S127000, C427S162000, C427S240000, C428S064200, C428S064200, C428S064400, C428S690000
Reexamination Certificate
active
06715200
ABSTRACT:
FEDERALLY SPONSORED RESEARCH
Not Applicable
TECHNICAL FIELD
The present disclosure relates to data storage media and methods for making such media, and especially relates to methods of making data storage media and to partially and wholly plastic data storage media.
BACKGROUND OF THE INVENTION
Optical, magnetic and magneto-optic media are primary sources of high performance storage technology, which enables high storage capacity coupled with a reasonable price per megabyte of storage. Areal density, typically expressed as billions of bits per square inch of disk surface area (Gbits per square inch (Gbits/in
2
)), is equivalent to the linear density (bits of information per inch of track) multiplied by the track density in tracks per inch. Improved areal density has been one of the key factors in the price reduction per megabyte, and further increases in areal density continue to be demanded by the industry.
In the area of optical storage, advances focus on access time, system volume, and competitive costing. Increasing areal density is being addressed by focusing on the diffraction limits of optics (using near-field optics), investigating three dimensional storage, investigating potential holographic recording methods and other techniques.
Conventional polymeric data storage media has been employed in areas such as compact disks (CD-ROM) and recordable or re-writable compact disks (e.g., CD-RW), and similar relatively low areal density devices, e.g. less than about 1 Gbits/in
2
, which are typically read-through devices requiring the employment of a good optical quality substrate having low birefringence.
Referring to
FIG. 1
, a low areal density system
1
is illustrated having a read device
3
and a recordable or re-writable storage media
5
. The storage media
5
comprises conventional layers, including a data layer
7
, dielectric layers
9
and
9
′, reflective layer
11
, and protective layer
13
. During operation of the system
1
, a laser
15
produced by the read device
3
is incident upon the optically clear substrate
17
. The laser passes through the substrate
17
, and through the dielectric layer
9
, the data layer
7
and a second dielectric layer
9
′. The laser
15
then reflects off the reflective layer
11
, back through the dielectric layer
9
′, the data layer
7
, the dielectric layer
9
, and the substrate
17
and is read by the read device
3
.
Unlike the CD and beyond that of the DVD, storage media having high areal density capabilities, typically greater than 5 Gbits/in
2
, employ first surface or near field read/write techniques in order to increase the areal density. For such storage media, although the optical quality of the substrate is not relevant, the physical and mechanical properties of the substrate become increasingly important. For high areal density applications, including first surface applications, the surface quality of the storage media can effect the accuracy of the reading device, the ability to store data, and replication qualities of the substrate. Furthermore, the physical characteristics of the storage media when in use can also effect the ability to store and retrieve data; i.e. the axial displacement of the media, if too great, can inhibit accurate retrieval of data and/or damage the read/write device.
Conventionally, the above issues associated with employing first surface, including near field, techniques have been addressed by utilizing metal, e.g., aluminum, and glass substrates. These substrates are formed into a disk and the desired layers are disposed upon the substrate using various techniques, such as sputtering. Possible layers include reflective layers, dielectric layers, data storage layers and protective layers. Once the desired magnetic layers have been added, the disk may be partitioned into radial and tangential sectors through magnetic read/write techniques. Sector structure may also be added through physical or chemical techniques, e.g. etching, however this must occur prior to the deposition of the magnetic layers.
As is evident from the fast pace of the industry, the demand for greater storage capacities at lower prices, the desire to have re-writable disks, and the numerous techniques being investigated, further advances in the technology are constantly desired and sought. What is needed in the art are advances in storage media substrate materials enabling storage media to be utilized in first surface, including near field, applications.
BRIEF SUMMARY OF THE INVENTION
Methods for forming data storage media and the media formed thereby are disclosed herein. In one embodiment, the method for forming a data storage media comprises: forming a substrate; disposing a plastic layer on at least one surface of a substrate; embossing the plastic layer by heating a first substrate to a temperature above a substrate surface glass transition temperature, preheating and maintaining a mold at a mold temperature below said substrate surface glass transition temperature, introducing said heated substrate to said preheated mold, compressing said heated substrate in said mold, cooling said compressed substrate, and removing said cooled substrate from said mold; and disposing a data layer over said plastic layer; wherein said data storage media has an axial displacement peak of less than about 500&mgr; under shock or vibration excitation.
In another embodiment, the method for forming a data storage media, comprises: forming a substrate; disposing a plastic layer on at least one surface of a substrate; embossing the plastic layer by heating a first substrate to a temperature above a substrate surface glass transition temperature, preheating a mold to a mold temperature of up to about 30° C. above said substrate surface glass transition temperature, introducing said heated substrate to said preheated mold, compressing said heated substrate in said mold, cooling said compressed substrate, and removing said cooled substrate from said mold; and disposing a data layer over said plastic layer; wherein said data storage media has an axial displacement peak of less than about 500&mgr; under shock or vibration excitation.
In yet another embodiment, the method for forming a data storage media, comprises: injection molding a substrate comprising surface features, wherein said surface features have greater than about 90% of a surface feature replication of an original master; and disposing a data layer over at least one surface of said substrate; wherein said data storage media has an axial displacement peak of less than about 500&mgr; under shock or vibration excitation.
REFERENCES:
patent: 3198657 (1965-08-01), Kimball et al.
patent: 4020278 (1977-04-01), Carre et al.
patent: 4057831 (1977-11-01), Jacobs et al.
patent: 4206256 (1980-06-01), Matthies et al.
patent: 4211617 (1980-07-01), Hunyar et al.
patent: 4222070 (1980-09-01), Howe et al.
patent: 4235835 (1980-11-01), Stutzman et al.
patent: 4243317 (1981-01-01), Garbe et al.
patent: 4267212 (1981-05-01), Sakawaki
patent: 4272474 (1981-06-01), Crocker
patent: 4305081 (1981-12-01), Spong
patent: 4329697 (1982-05-01), Bell
patent: 4363844 (1982-12-01), Lewis et al.
patent: 4373065 (1983-02-01), Prest, Jr.
patent: 4402798 (1983-09-01), Gorog et al.
patent: 4404238 (1983-09-01), Baldwin
patent: 4415942 (1983-11-01), Frosch et al.
patent: 4419704 (1983-12-01), Radman et al.
patent: 4430387 (1984-02-01), Nakagawa et al.
patent: 4441179 (1984-04-01), Slaten
patent: 4451507 (1984-05-01), Beltz et al.
patent: 4457259 (1984-07-01), Samuels
patent: 4492718 (1985-01-01), Mayer et al.
patent: 4503420 (1985-03-01), Rub et al.
patent: 4514583 (1985-04-01), Izu et al.
patent: 4515828 (1985-05-01), Economy
patent: 4519065 (1985-05-01), Lewis et al.
patent: 4552820 (1985-11-01), Lin et al.
patent: 4554655 (1985-11-01), Kumasaka et al.
patent: 4569871 (1986-02-01), Ohmori et al.
patent: 4584259 (1986-04-01), Mayer et al.
patent: 4590493 (1986-05-01), Inoue et al.
patent: 4592939 (1986-06-01), Temple et al.
patent: 4596739 (1986-06-01), Piltingsrud et al.
patent: 4596740 (1986
Bushko Wit C.
Cole Herbert S.
Davis John E.
Feist Thomas P.
Gorczyca Thomas B.
Kim Paul D
Vo Peter
LandOfFree
Methods for making data storage media does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Methods for making data storage media, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Methods for making data storage media will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3264497