Magnetic Recording Medium Dimensional Stability
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Solution Overview
Problem
Magnetic recording media face dimensional changes in the track width direction due to environmental factors like temperature and humidity, leading to off-track phenomena during long-term storage, which existing technologies struggle to mitigate without increasing tape thickness or compromising recording capacity.
Innovation Solution
A magnetic recording medium with a specific layer structure comprising a magnetic layer, a non-magnetic layer, and a base layer, where the average thickness is ≤5.5 μm, and the dimensional variation to tension change is ≤660 ppm/N, with a non-magnetic layer thickness ≤1.0 μm, and a surface roughness of 3.0 nm to 7.5 nm, allowing for stable width maintenance and increased recording capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the track width and distance between tracks are reduced to improve data recording density, then the recording capacity is improved, but the dimensional variation of the tape becomes more significant leading to off-track phenomena
Solution Approach 1:
The patent applies parameter changes by controlling the Poisson's ratio of the base layer within a specific range (0.25 ≤ ν < 0.35) to suppress dimensional variation in the width direction. This parameter optimization allows the tape to maintain dimensional stability even when track width is reduced, thereby resolving the contradiction between high recording density and dimensional precision
Solution Approach 2:
The patent uses a composite structure consisting of a base layer and a magnetic layer, where the base layer is made of a specific polymer material with controlled Poisson's ratio. This composite material approach enables the tape to achieve both high recording capacity and dimensional stability simultaneously
2Stability of the object's composition
If the tape thickness is increased to suppress dimensional change, then the dimensional stability is improved, but the recording capacity is reduced
Solution Approach 1:
The patent changes the Poisson's ratio parameter of the base layer to a specific range (0.25 ≤ ν < 0.35), which fundamentally alters the dimensional response characteristics of the tape. This enables thin tapes (≤5.5 μm) to exhibit dimensional stability comparable to or better than thicker tapes, thus resolving the contradiction between thickness and stability without sacrificing recording capacity
3Productivity
If the non-magnetic layer thickness is reduced to increase recording capacity, then the recording density is improved, but the dimensional control becomes more difficult
Solution Approach 1:
The patent optimizes the Poisson's ratio of the base layer to compensate for the reduced non-magnetic layer thickness. By controlling ν within 0.25 ≤ ν < 0.35, the base layer provides sufficient dimensional stability even when the non-magnetic layer is thin (≤1.0 μm), allowing high recording density to be achieved without compromising dimensional control
Data Source
AI summary
A magnetic recording medium is provided and includes a layer structure including a magnetic layer, a non-magnetic layer, and a base layer in order, in which an average thickness tT of the magnetic recording medium is 4.0 μm≤tT≤5.3 μm, a dimensional variation Δw in a width direction of the magnetic recording medium to tension change in a longitudinal direction of the magnetic recording medium is 680 ppm/N≤Δw≤2000 ppm/N, and an average thickness tn of the non-magnetic layer is tn≤1.0 μm.