Slider Cleaning via Modulation Contact Detection in HAMR
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Solution Overview
Problem
In heat-assisted magnetic recording (HAMR) systems with low- or non-modulation head-disk interfaces, contamination on the slider affects the accuracy of friction-based contact detection, leading to premature indication of head-medium contact, which is critical for maintaining optimal slider clearance and recording performance.
Innovation Solution
A method and apparatus that utilize modulation-based contact detection to dislodge contaminants from the slider at specific locations where modulation-based detection is reliable, followed by friction-based contact detection to ensure accurate head-medium contact sensing, thereby maintaining optimal slider clearance and improving detection reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If friction-based contact detection is used, then contact sensing is simple and direct, but contamination on the slider causes premature indication of head-medium contact
Solution Approach 1:
The patent applies preliminary action by performing modulation-based contact detection before friction-based contact detection to clean the slider surface. The modulation-based detection is used to dislodge contaminants from the slider before the friction-based sensor makes contact with the medium, ensuring the sensor surface is clean and ready for accurate friction-based measurement.
Solution Approach 2:
The patent uses modulation-based contact detection as an intermediary mechanism to remove contaminants before the primary friction-based detection occurs. This intermediary cleaning process allows the friction-based sensor to operate accurately without being affected by surface contamination.
2Reliability
If modulation-based contact detection is used to clean the slider, then contamination is removed, but the process adds complexity to the detection system
Solution Approach 1:
The patent applies multi-functionality by using the modulation-based contact detection system for dual purposes: normal contact detection operations and slider cleaning operations. The same modulation-based detection infrastructure serves both functions, eliminating the need for separate cleaning hardware and reducing overall system complexity.
Solution Approach 2:
The patent implements self-service by using the existing modulation-based contact detection system to clean the slider during normal operation. The system utilizes its own operational signals and infrastructure to perform the cleaning function without requiring external intervention or separate cleaning mechanisms.
3Manufacturing precision
If modulation-based contact detection is performed at all locations, then complete cleaning is achieved, but reliable detection is only possible at specific locations
Solution Approach 1:
The patent applies local quality by performing modulation-based contact detection at specific locations on the recording medium where the signal is most reliable and strong, rather than attempting uniform cleaning across all locations. The cleaning is concentrated at locations where the modulation-based detection can most effectively dislodge contaminants, optimizing both cleaning effectiveness and detection reliability.
Data Source
AI summary
A slider is configured for heat-assisted magnetic recording to a magnetic recording medium. A low- or non-modulation interface is defined between the slider and the medium. A contaminant is present on the slider and between the slider and the medium. A controller is configured to control the slider to dislodge the contaminant from the slider by performing modulation-based contact detection at a location of the medium where modulation-based contact detection can accurately detect head-medium contact. The controller is also configured to perform friction-based contact detection using the slider devoid of the contaminant.