Split Contact Sensor for HAMR Slider Contamination
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Solution Overview
Problem
In heat-assisted magnetic recording (HAMR) technology, contaminant buildup on contact sensors leads to inaccurate detection of head-to-medium contact and insensitivity to laser-induced protrusions, causing early contact triggers and performance degradation due to their positioning within the contaminant buildup region.
Innovation Solution
A split contact sensor is positioned outside the contaminant buildup region, with a first and second ABS section spaced apart by a gap, and a distal section connecting them, allowing reliable detection of head-to-medium contact and laser-induced protrusions while avoiding contaminant accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a contact sensor is positioned within the contaminant buildup region to detect head-to-medium contact, then contact detection capability is improved, but measurement precision deteriorates due to contaminant accumulation on the sensor
Solution Approach 1:
The contact sensor is divided into multiple sections: a first ABS section positioned within the contaminant buildup region for contact detection, a second ABS section positioned outside the contaminant buildup region, and a distal section connecting them. This segmentation allows the sensor to maintain detection capability while avoiding contaminant accumulation on the active sensing area.
Solution Approach 2:
The second ABS section is extracted and positioned outside the contaminant buildup region, separating the sensing function from the contaminant exposure area. This extraction ensures that contaminants do not accumulate on the sensor surface, maintaining measurement precision over time.
2Measurement precision
If a contact sensor is positioned close to the laser source to detect laser-induced protrusions, then detection sensitivity is improved, but the sensor becomes insensitive to protrusions due to contaminant buildup
Solution Approach 1:
The sensor is segmented into first and second ABS sections with different positioning relative to the contaminant buildup region. The first section detects contact while the second section remains clean, enabling continuous accurate measurement of protrusions without degradation from contamination.
3Reliability
If a continuous contact sensor is used for reliable contact detection, then detection reliability is improved, but the sensor structure becomes more complex and susceptible to contaminant accumulation
Solution Approach 1:
The continuous sensor is divided into discrete sections (first ABS section, second ABS section, and distal section) connected by a non-conductive path. This segmentation maintains detection reliability through the first section while the second section provides contamination resistance, and the modular structure simplifies manufacturing compared to a fully continuous sensor.
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 split contact sensor provides reliable and consistent contact detection signals, preventing early contact triggers and maintaining accurate head-to-medium clearance settings despite contaminant buildup, enhancing the performance and reliability of HAMR devices.
Implementation Method 1
An optical waveguide is configured to couple light from a laser source to the NFT
Implementation Method 2
A writer having a write pole is situated at or near the ABS. An NFT is situated at or near the ABS and between the write pole and the leading edge of the slider
Data Source
AI summary
An apparatus comprises a slider having an air bearing surface (ABS), a leading edge, and a trailing edge opposing the leading edge. A writer having a write pole is situated at or near the ABS. A near-field transducer (NFT) is situated at or near the ABS and between the write pole and the leading edge of the slider. An optical waveguide is configured to couple light from a laser source to the NFT. A contact sensor is situated between the write pole and the trailing edge. The contact sensor comprises a first ABS section situated at or near the ABS, a second ABS section situated at or near the ABS and spaced apart from the first ABS in a cross-track direction by a gap, and a distal section extending away from the ABS and connecting the first ABS section with the second ABS section.