Dual-Layer Magnetic Disk Servo Recording for High Track Density
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Solution Overview
Problem
Conventional magnetic storage apparatuses face challenges in improving track density in the data region of magnetic recording media due to limitations in magnetic field intensity and head design, which hinder the increase in recording capacity.
Innovation Solution
A servo information recording method where servo information is continuously recorded on a magnetic disk with a magnetic head, partially overlapping adjacent tracks in a radial direction, using a dual recording layer structure with different coercivity levels, allowing for improved track density and recording capacity by optimizing the magnetic field distribution and head positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the distance between the magnetic head and the first recording layer is increased to record servo information, then the coercivity requirement is met, but the magnetic field intensity reaching the recording layer becomes low, deteriorating recording characteristics
Solution Approach 1:
The patent introduces a dual-layer recording structure where servo information is recorded in the first recording layer at a greater distance from the magnetic head, while data information is recorded in the second recording layer closer to the magnetic head. This dimensional separation in the radial direction allows each layer to be optimized for its specific recording requirements without compromising the other.
Solution Approach 2:
The patent applies different coercivity values to different recording layers - the first recording layer has higher coercivity suitable for servo information recording, while the second recording layer has lower coercivity optimized for data recording. This local differentiation of magnetic properties allows each layer to be tailored to its specific functional requirements.
2Manufacturing precision
If the magnetic field intensity is increased to improve recording characteristics, then the recording quality improves, but the track density deteriorates due to magnetic field spread
Solution Approach 1:
By recording servo information and data information in separate radial layers, the patent allows independent optimization of magnetic field parameters for each layer. The data recording layer can use higher magnetic field intensity for better recording characteristics without compromising track density, as the servo layer is positioned where field spread is less critical.
Solution Approach 2:
The patent segments the recording medium into functionally distinct layers - the first recording layer for servo information and the second recording layer for data information. This segmentation allows each layer to be optimized independently for its specific requirements, including magnetic field intensity and track density.
3Device complexity
If a single recording layer is used for both servo information and data, then the structure is simple, but the data region area is reduced due to servo region occupation
Solution Approach 1:
The patent utilizes the radial dimension of the magnetic recording medium by creating multiple recording layers at different radial positions. Servo information is recorded in the first recording layer while data information is recorded in the second recording layer, allowing both functions to coexist without spatial conflict in the planar view, thereby maximizing the data region area.
Solution Approach 2:
The patent merges the servo recording function and data recording function into a unified dual-layer structure, where both functions operate simultaneously in different radial layers. This integration eliminates the need for separate servo and data regions in the planar view, maximizing the usable data storage area.
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 approach enhances the track density and recording capacity of the magnetic disk by allowing for more efficient data recording and reproduction, particularly by utilizing a dual recording layer structure with overlapping servo information tracks, thereby improving the magnetic head's recording characteristics and thermal stability.
Implementation Method 1
the intensity of the magnetic field output from the magnetic head and reaching the lower layer part becomes low
Implementation Method 2
a magnetic layer including a lower layer part and an upper layer part, each having a different coercivity
Data Source
AI summary
A servo information recording method continuously records servo information in a radial direction of a magnetic disk on a plurality of concentric tracks or on a single spiral track of a first recording layer that forms a magnetic layer of the magnetic disk together with a second recording layer to which data are recorded and from which data are reproduced, wherein the first recording layer has a coercivity higher than that of the second recording layer, and partially overlaps two mutually adjacent tracks when continuously recording the servo information on an entire surface of the first recording layer.