Multilevel Magnetic Recording Head Using Variable Current States
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Solution Overview
Problem
Current magnetic data storage technologies face limitations in increasing areal density, as they can only store data in two states per region, limiting the amount of data that can be stored per unit area while maintaining cost-effectiveness.
Innovation Solution
The method involves applying two or more different recording currents, including positive, negative, and zero or near-zero currents, to a write coil of a recording head to create regions on a magnetic medium that can store three or more magnetic states, enabling multilevel recording and reading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If two or more different recording currents are applied to the write coil, then data storage capacity per unit area increases, but device complexity increases
Solution Approach 1:
The patent applies parameter changes by utilizing multiple recording current levels (positive, negative, and zero or near-zero currents) to create distinct magnetic states in each recorded region. This allows each physical location on the magnetic medium to store multiple data states (three or more states per unit of data), thereby increasing storage capacity without adding physical storage locations. The write coil's current parameter is varied to encode multiple states, resolving the contradiction between storage capacity and device complexity.
2Quantity of substance
If each region stores three or more magnetic states, then areal density increases, but measurement precision requirements increase
Solution Approach 1:
The patent employs preliminary action through AC erasing the magnetic medium before recording. This erasure step prepares the medium by creating a uniform magnetic state, which enhances the distinction between subsequent recorded states. By pre-conditioning the medium, the read transducer can more easily distinguish between multiple magnetic states, thereby supporting higher areal density while managing the increased measurement precision requirements through improved signal differentiation.
3Productivity
If multiple recording currents are used to create multiple magnetic states, then data storage efficiency improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent utilizes periodic action through AC erasing, where an alternating current is applied to the write coil at a frequency sufficient to erase previously recorded data. This periodic erasure creates a consistent starting state for each recording operation, ensuring uniformity across the magnetic medium. By systematically preparing the medium before recording multiple states, the process achieves high storage efficiency while maintaining manufacturability through repeatable, controlled operations.
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 allows for storing up to n/2 times more data per unit area by extending each bit to store multiple states, thereby enhancing data storage capacity and efficiency.
Implementation Method 1
two or more different recording currents are applied to a write coil of a recording head... In response to the application of the two or more different recording currents, a data stream is recorded to regions of a moving continuous magnetic recording medium
Implementation Method 2
The three or more magnetic states are read from the continuous magnetic recording medium via a magnetic read transducer to recover the data stream
Data Source
AI summary
Two or more different recording currents are applied to a write coil of a recording head. A first of the two or more currents is a positive current and a second of the two or more currents is a negative current. In response to the application of the two or more different recording currents, a data stream is recorded to regions of a moving continuous magnetic recording medium such that each region has three or more magnetic states. The three or more magnetic states can be read from the continuous magnetic recording medium via a magnetic read transducer to recover the data stream.