Data storage media

Abstract

The data storage media comprises, in a preferred embodiment, a homogenous or non-homogenous plastic substrate that can be formed in situ with the desired surface features disposed thereon on one or both sides, a data storage layer such as a magneto-optic material also on one or both sides, and an optional protective, dielectric, and/or reflective layers. The substrate can have a substantially homogenous, tapered, concave, or convex geometry, with various types and geometries of reinforcement employed to increase stiffness without adversely effecting surface integrity and smoothness.

Description

[0001] This application is a continuation application of U.S. patent application Ser. No. 09 / 502,968 filed Feb. 11, 2000, and also claims the benefit of the filing date of U.S. Provisional Application Ser. Nos. 60 / 120,101 filed Feb. 12, 1999, Attorney Docket Nos. GP2-0001 and 8CN-8803PA; 60 / 134,585 filed May 17, 1999, Attorney Docket No. 8CN-8807PA; 60 / 137,883 filed Jun. 7, 1999, Attorney Docket No. 8CU-5845PA; 60 / 137,884 filed Jun. 7, 1999, Attorney Docket Nos. 8CU-5846PA; and 60 / 146,248 filed Jul. 29, 1999, Attorney Docket No. 8CN-8826PA and GP2-0018; the entire contents of each application are hereby incorporated by reference.BACKGROUND OF INVENTION[0002] Optical, magnetic and magneto-optic media are primary sources of high performance storage technology that 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 .sup.2)), is...

AI Technical Summary

Benefits of technology

0050] Adjusting the geometry of the substrate enables manipulation of the moment of inertia of the substrate when rotating, and control of the modal responses, i.e. the harmonics thereof. For example, various modal shapes (as shown in FIG. 36) can be obtained and avoided, based upon sectional variations in density through planar and / or radial thickness. As stated above, the preferred design is a substrate having a first modal resonance frequency outside of the frequency range for which the storage media is designed.

0051] Another manner of addressing the various design criteria for the storage media is addressing its use, such as its operating rotational speed which effects the speed in which data can be stored / retrieved. Conventionally, during use, storage media has been rotated at a constant speed. The media is brought to its operating rotational speed prior to any reading or writing. However, the storage media can be rotated at a varied speed where the speed increases during peak use periods while decreasing during normal use periods; or rotational speed can be varied in order to maintain constant linear velocity at different areas of the disk (e.g., inner vs. outer diameter). Such operating criteria will both conserve energy and potentially render some design criteria more important. Such criteria include, e.g., moment of inertia, modulus, density, viscoelasticity, thickness, and / or diameter to name a few. Storage media devices that change speeds make many of these criteria, e.g., moment of inertia and density, etc. of increased importance as compared to constant speed devices.

Problems solved by technology

Furthermore, the physical characteristics of the storage media when in use can also affect 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.

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