Dual Thermal Fly-Height Control for Magnetic Recording Heads
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Solution Overview
Problem
Conventional magnetic recording heads face a tradeoff between linear density and track density, leading to decreased reliability and increased costs due to the need for multiple write heads and complex electrical circuits, which limits signal-to-noise ratio and bit per track inch capability.
Innovation Solution
A magnetic recording head design featuring a first wide-writing write head and a second narrow-writing write head, both coupled to a shared electrical circuit with a capacitor and inductor sub-circuits, allowing independent thermal fly height control and power management, reducing the number of pads required on the slider pad and optimizing bit per inch and track per inch capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a wide-writing write head is used to increase linear density (BPI), then BPI capability is improved, but track edge curvature increases which limits TPI capability and introduces adjacent track interference
Solution Approach 1:
The magnetic recording head is divided into two separate write heads: a first write head with a wide write pole for high BPI capability and a second write head with a narrow write pole for high TPI capability. This segmentation allows each head to be optimized for its specific function, with the wide write head achieving high linear density while the narrow write head minimizes track edge curvature and adjacent track interference for high track density.
2Productivity
If dual write heads are used to balance BPI and TPI, then both linear and track density are improved, but the number of electrical pads required increases to three or four pads on the slider body
Solution Approach 1:
The first write head and second write head share common electrical circuitry and thermal fly height control elements. Specifically, both write heads utilize the same thermal fly height control (TFC) element and share electrical connections, reducing the total number of pads required on the slider body from three or four to fewer connections. This merging approach maintains dual-write capability for optimized BPI and TPI while reducing device complexity and wire bonding requirements.
3Area of stationary object
If the slider pad size is reduced to accommodate multiple pads for dual write heads, then device footprint is minimized, but manufacturing costs increase and reliability decreases due to complex wire bonding
Solution Approach 1:
By merging the electrical circuits and thermal fly height control elements between the first and second write heads, the design reduces the number of discrete pads required on the slider body. This reduction in pad count simplifies the wire bonding architecture, thereby improving reliability while maintaining a compact slider pad footprint.
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 enhances areal density capacity by reducing track edge curvature, minimizing adjacent and far track interference, and lowering manufacturing costs by reducing the slider pad size and complexity.
Implementation Method 1
The electrical circuit comprises a first sub-circuit and a second sub-circuit connected in parallel. The first sub-circuit comprises a capacitor and a connection to a first thermal fly height control (TFC) of the first write head.
Implementation Method 2
The second sub-circuit comprises an inductor and a connection to a second TFC of the second write head.
Implementation Method 3
The electrical circuit is configured to independently power the first thermal fly height element and the second thermal fly height element
Data Source
AI summary
The present disclosure generally relates to a magnetic media drive employing a magnetic recording head. The magnetic recording head comprises a first write head and a second write head each coupled to a first pad and a second pad of a slider pad and an electrical circuit coupled to the first and second pads. The first write head is a wide writing write head, and the second write head a narrow writing write head. The electrical circuit comprises a first sub-circuit and a second sub-circuit connected in parallel. The first sub-circuit comprises a capacitor and a connection to a first thermal fly height control (TFC) of the first write head. The second sub-circuit comprises an inductor and a connection to a second TFC of the second write head. The electrical circuit is further connected to a third TFC of a read head, the second write head comprising the read head.