Magnetic Recording Medium Surface Flatness and Adhesion
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Solution Overview
Problem
Conventional discrete track magnetic recording media face issues with track density due to interference from adjacent tracks, leading to degraded adhesion of embedding layers and damage to magnetic heads, and uneven surface heights affecting flying properties.
Innovation Solution
A magnetic recording medium with a substrate and a magnetic recording layer featuring patterns of protrusions and recesses, where the magnetic recording layer in recesses has a thickness less than two-thirds of the protrusions, and the difference in height is maintained at 7 nm or less, either without an embedding layer or with improved adhesion through contact with the same material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the magnetic recording layer is completely removed from recesses to flatten the surface, then the surface flatness is improved, but the adhesion of the embedding layer deteriorates due to contact with different materials
Solution Approach 1:
The patent applies local quality by selectively removing the magnetic recording layer only from the recess portions while leaving it intact on the protrusions. This creates different local structures: recesses with embedding layer only, and protrusions with both magnetic recording layer and embedding layer, optimizing both surface flatness and adhesion in different regions
Solution Approach 2:
Instead of completely removing the magnetic recording layer from all recesses, the patent applies partial action by removing it only to a controlled extent, leaving a residual thickness of 1 nm or more. This partial removal achieves sufficient surface flatness while maintaining enough magnetic layer to preserve adhesion properties
2Shape
If the magnetic recording layer is completely removed from recesses, then the embedding layer can be filled to flatten the surface, but peeling of the embedding layer occurs during operation
Solution Approach 1:
The patent applies beforehand cushioning by leaving a residual magnetic recording layer (1 nm or more) in the recesses before the embedding layer is formed. This residual layer acts as a cushioning interface that prevents direct contact between the embedding layer and the underlayer, thereby preventing peeling during subsequent operation
3Manufacturing precision
If a large difference in height is created on the medium surface, then the discrete track structure is achieved, but the flying properties of the magnetic head are degraded
Solution Approach 1:
The patent applies parameter changes by precisely controlling the depth of recesses and the residual thickness of the magnetic recording layer (1 nm or more). This parameter optimization achieves sufficient track separation for discrete track structure while maintaining surface height differences small enough (7 nm or less) to preserve magnetic head flying properties
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances track density, prevents peeling of the embedding layer, and improves flying stability of the magnetic head by maintaining a low touchdown pressure and accurate servo tracking.
Implementation Method 1
a magnetic recording layer formed on the substrate and having patterns of protrusions and recesses
Data Source
AI summary
According to one embodiment, a magnetic recording medium includes a substrate, and a magnetic recording layer formed on the substrate and having patterns of protrusions and recesses corresponding to a servo area and a recording area, in which the magnetic recording layer located in each of the recesses in the recording area has a thickness smaller than two thirds of a thickness of the magnetic recording layer corresponding to each of the protrusions, the magnetic recording layer remaining in each of the recesses in the recording area has a thickness of 1 nm or more, and a difference in height on a surface of the magnetic recording medium is 7 nm or less.