Perpendicular Recording Head Pole Shaping for Straight Bit Transitions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Perpendicular magnetic recording heads face challenges in achieving straight transitions between magnetic bits, leading to reduced linear data densities due to curved transitions caused by the shape of the magnetic field beneath the main pole, which limits the ability to distinguish between adjacent bits as bit sizes decrease.
Innovation Solution
A perpendicular recording head design featuring a writer pole with a concave facing surface and a top shield with a convex surface, along with a gap layer and optional bottom pole, to create a combined magnetic field that allows for writing perpendicular data bits with straighter transitions, utilizing double-reversed pancake coils to ensure magnetic fields circulate in opposite directions and maintain orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional main pole with a rectangular exposed surface is used, then the magnetic field is easy to generate, but the transitions between magnetic bits become curved which limits linear data density
Solution Approach 1:
The main pole is divided into multiple segments: a writer pole with a concave facing surface and a top shield with a convex surface. This segmentation allows each component to contribute differently to the magnetic field shape, with the concave-convex combination working together to produce straighter transitions while maintaining manufacturing feasibility through modular construction
Solution Approach 2:
The invention introduces a new dimensional aspect by adding the top shield structure above the writer pole, creating a three-dimensional magnetic field confinement system. The convex surface of the top shield and concave surface of the writer pole work in conjunction to reshape the magnetic field distribution in the vertical dimension, transforming the field geometry to achieve straighter transitions
2Productivity
If the size of magnetic bits is reduced to increase linear data density, then more data can be stored, but the curved transitions overlap and become indistinguishable
Solution Approach 1:
The invention strategically applies curvature in reverse - using a concave surface on the writer pole and a convex surface on the top shield to counteract the natural rounding of magnetic field transitions. This inverse curvature approach straightens the transitions by compensating for the repulsive effects of flux lines, enabling clear distinction between adjacent bits even at reduced sizes
Solution Approach 2:
The invention changes the geometric parameters of the pole surfaces from flat to curved (concave and convex respectively). This parameter modification fundamentally alters the magnetic field distribution pattern, transforming curved transitions into straight transitions and enabling higher linear data density without transition overlap
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
The design enables the writing of magnetic bits with straighter transitions, enhancing linear data densities by preventing curvature and ensuring clear distinction between adjacent bits, thus overcoming the limitations of curved transitions in existing technologies.
Implementation Method 1
When an electric current is passed through the coil windings 170, a magnetic field is induced in the main pole 150 and the secondary pole 160
Implementation Method 2
Lines of magnetic flux 180 from the magnetic field extend between the exposed surfaces of the main pole 150 and the secondary pole 160 to complete the magnetic loop around the coil windings 170
Data Source
AI summary
A perpendicular recording head is provided having a bottom pole, a writer pole disposed above the bottom pole, and a top shield disposed above the writer pole. The bottom pole and the top shield are both magnetically coupled to the writer pole. The writer pole includes a concave facing surface that faces the top shield. The top shield can include a convex surface that faces the writer pole. The top shield can also include a pedestal that protrudes towards the writer pole.