HAMR Head Heat Dissipation Detection and Mitigation
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Solution Overview
Problem
Data storage devices, such as hard disk drives, face degradation and potential failure due to changes in heat dissipation of energized and heated components, which can lead to non-nominal thermal and electrodynamic effects, affecting head performance and posing risks of cascading degradation and failure.
Innovation Solution
Incorporating control circuitry that intermittently measures the temperature-current relation of heated components, such as laser units, to detect deviations from nominal heat dissipation, and performs mitigation actions, like mechanical or chemical adjustments, to maintain optimal operation and provide advance warning of impending failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If heat-assisted magnetic recording (HAMR) is used to enable high data density, then writing capability is improved, but heat dissipation increases causing head degradation and reliability issues
Solution Approach 1:
The patent applies preliminary action by measuring the temperature-current relation of the laser unit before it causes significant degradation. The system intermittently measures this relation and compares it to a nominal value, detecting deviations early in the degradation process. This allows the system to identify potential head failures before they occur, enabling proactive mitigation actions such as adjusting operating parameters or alerting users to backup data, thereby preventing catastrophic failures while maintaining high data density operations
Solution Approach 2:
The patent implements feedback by continuously monitoring the temperature-current relation of the laser unit and using this information to adjust operations. The control circuitry measures the actual temperature at different current levels, compares the measured relation to the nominal temperature-current relation, and detects deviations that indicate degradation. This feedback loop enables the system to adapt to changing head conditions, maintaining reliable operation while utilizing HAMR for high-density recording
2Power
If laser units are energized to heat tracks for writing, then write capability is improved, but non-nominal heat dissipation causes head degradation
Solution Approach 1:
The patent applies parameter changes by monitoring the temperature-current relation parameters of the laser unit to detect degradation. Instead of simply monitoring absolute temperature, the system measures the relationship between current and temperature across multiple current levels. This parameter-based approach allows detection of subtle changes in heat dissipation characteristics that indicate degradation, enabling the system to adjust operating parameters or alert users before failure occurs, thus managing the harmful effects of heat dissipation while maintaining write capability
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 extends the operational life of disk drive heads, reduces the risk of unanticipated failure, and allows for orderly data backup by detecting and mitigating non-nominal heat dissipation, ensuring stable performance and preventing catastrophic head-disk contact.
Implementation Method 1
a temperature sensor; and one or more processing devices configured to: detect, via the temperature sensor, a non-nominal heat dissipation of a portion of the head
Implementation Method 2
a laser unit and a near-field transmitter (NFT) used in a HAMR head
Implementation Method 3
A heat-assisted magnetic recording (HAMR) disk drive may use disk surfaces that enable stable, high data density by requiring heating to be written to
Data Source
AI summary
Various illustrative aspects are directed to a data storage device, comprising one or more disks; a head, configured to be positioned proximate to a disk surface among the one or more disks; a temperature sensor; and one or more processing devices. The one or more processing devices are configured to: detect, via the temperature sensor, a non-nominal heat dissipation of a portion of the head; and, in response to detecting the non-nominal heat dissipation of the portion of the head, mitigate the non-nominal heat dissipation of the portion of the head.