HAMR Head Dynamic Flying Height Control Mechanism
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Solution Overview
Problem
Maintaining accurate flying height of a heat-assisted magnetic recording (HAMR) head is challenging due to the presence of a heating source like a laser, leading to potential data corruption and increased costs in data preservation processes, which affects data integrity and device performance.
Innovation Solution
Implementing a dynamic flying height (DFH) control mechanism that adjusts the flying height of the HAMR head using control circuitry and a closed-loop system, coupled with a preamplifier and timer, to ensure reliable data writing by maintaining a constant optimal flying height during write operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a heating source like a laser is used in HAMR head, then data writing capability is improved, but flying height stability deteriorates
Solution Approach 1:
The patent implements a feedback control system that continuously monitors the flying height of the HAMR head and dynamically adjusts the air bearing surface geometry to compensate for thermal expansion caused by the laser heating source. This closed-loop control maintains flying height stability despite the presence of the heating element, resolving the contradiction between improved data writing capability and deteriorated flying height stability.
Solution Approach 2:
The patent dynamically changes the physical parameters of the air bearing surface, specifically adjusting the flying height as a function of radial position on the disk. By modifying the air bearing geometry in response to thermal conditions, the system maintains optimal flying height stability while allowing the laser to provide improved data writing capability.
2Reliability
If data preservation processes are increased to ensure data integrity, then data reliability is improved, but device availability and interface function performance deteriorate
Solution Approach 1:
The patent performs preliminary actions by dynamically adjusting the flying height before data writing operations to prevent potential data corruption. By proactively controlling the HAMR head position and maintaining optimal flying height, the system prevents errors before they occur, eliminating the need for subsequent data preservation processes and verification steps, thus maintaining both high data reliability and device availability.
3Speed
If flying height is not maintained accurately, then interface operation speed is improved, but data integrity deteriorates
Solution Approach 1:
The patent implements a dynamic flying height control system that continuously adapts the HAMR head position based on radial location and thermal conditions. This dynamic adjustment maintains accurate flying height throughout data writing operations without requiring speed reductions, thereby preserving both high interface operation speed and data integrity simultaneously.
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 solution enhances data reliability and performance by ensuring accurate data writing, reducing the need for burdensome data preservation processes and minimizing the risk of data corruption, thereby improving overall system efficiency and reducing operational costs.
Implementation Method 1
The air bearing surface can be adjusted as a function of radial location on the magnetic media while writing data thereby maintaining a constant value of the flying height between the HAMR head and the magnetic media
Data Source
AI summary
An apparatus includes: a media; a heat assisted magnetic recording (HAMR) head over the media; and control circuitry, coupled to the HAMR head, the control circuitry being configured to: receive a write command to write the media; apply a dynamic flying height (DFH) control before asserting a write gate of the HAMR head; assert the write gate to the HAMR head; and enable a flying height compensation mechanism to maintain a constant value of a flying height of the HAMR head over the media during a next assertion of the write gate.