Magnetic Head Coil Winding for High Frequency Write Signals
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Solution Overview
Problem
Magnetic heads for perpendicular magnetic recording face challenges in reducing the length of the magnetic path while increasing the magnetomotive force, particularly in thermally-assisted magnetic recording systems where the presence of waveguides lengthens the magnetic path and requires efficient data writing with higher recording densities.
Innovation Solution
The magnetic head design includes a coil with specific winding configurations around core sections, where the second winding portion does not pass through the space defined by the magnetic path forming section, allowing for a reduced magnetic path length and increased magnetomotive force by optimizing the coil's winding angles and core section dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the magnetic path length is reduced to achieve higher frequency write signals, then the recording density increases, but the magnetomotive force of the coil decreases
Solution Approach 1:
The coil winding configuration transitions from a traditional planar arrangement to a three-dimensional structure where the coil winds around the core section in multiple layers. This spatial arrangement allows the coil to generate sufficient magnetomotive force even when the magnetic path length is reduced, as the multi-layer winding increases the effective number of turns within a compact volume.
Solution Approach 2:
The invention changes the geometric parameters of the coil winding, specifically the winding angle and the number of turns around the core section. By optimizing these parameters, the coil can maintain high magnetomotive force with a shorter magnetic path, enabling both high-frequency operation and sufficient writing capability.
2Length of stationary object
If the number of coil turns is reduced to shorten the magnetic path, then the magnetic path length decreases, but the magnetomotive force of the coil decreases
Solution Approach 1:
The coil is configured to wind around the core section in a three-dimensional manner rather than as a simple planar loop. This allows the coil to achieve effective multi-turn winding within a compact space, maintaining high magnetomotive force while keeping the magnetic path length short.
Solution Approach 2:
The coil winding structure embeds multiple turns within the core section geometry, where the coil passes through and around the core in a nested configuration. This maximizes the number of effective turns within the limited space defined by the short magnetic path.
3Productivity
If waveguides are added for thermally-assisted magnetic recording, then the recording density increases, but the magnetic path length increases
Solution Approach 1:
The magnetic path forming section is divided into distinct functional segments: a core section for magnetic flux concentration and a return path section for completing the magnetic circuit. This segmentation allows the waveguide to be positioned without forcing the magnetic flux to travel through extended paths, thus maintaining short magnetic path length while accommodating thermal assistance functionality.
Solution Approach 2:
The core section acts as an intermediary structure that concentrates and directs magnetic flux between the write head and the recording medium. This allows the waveguide to be positioned nearby for thermal assistance without requiring the magnetic path to extend to the waveguide, as the core section mediates the magnetic flux independently of the waveguide position.
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 design enables higher frequency write signals and increased recording densities by effectively reducing the magnetic path length and enhancing the magnetomotive force, addressing the limitations of existing magnetic head technologies.
Implementation Method 1
The coil produces a magnetic field corresponding to data to be written on the recording medium
Implementation Method 2
The magnetic path forming section forms a magnetic path for passing a magnetic flux corresponding to a magnetic field produced by the coil
Implementation Method 3
The main pole produces, from the first end face, a write magnetic field for writing the data on the recording medium
Data Source
AI summary
A magnetic head includes a coil, and a magnetic path forming section for defining a first space for a portion of the coil to pass through. The magnetic path forming section includes a core section. The coil includes a first winding portion and a second winding portion connected in series. The first winding portion includes one or two first coil elements extending to pass through the first space, and extends once or twice around the entire perimeter of the core section. The second winding portion does not pass through the first space, and extends less than once around the entire perimeter of the core section to rotate n degrees about a center point of the core section, where n is greater than 270 and smaller than 360.