Non-destructive Slider Contamination Detection via PES PSD Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for detecting contamination on sliders in data storage devices are destructive and invasive, requiring physical disassembly for microscopic evaluation, which is not suitable for non-destructive, non-intrusive detection.
Innovation Solution
A method and apparatus that utilize a slider's air bearing surface to support a read element adjacent a rotating data recording medium, extracting a non-repeatable runout (NRRO) component from position error signals (PES) and performing power spectral density (PSD) analysis to identify peak power levels, detecting contamination through statistical analysis of peak values using a two-sample t-test or threshold comparisons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If physical disassembly and microscopic evaluation are used to detect slider contamination, then detection accuracy is improved, but device integrity is compromised and detection process becomes complex
Solution Approach 1:
The patent replaces mechanical/physical inspection methods (microscopic evaluation requiring disassembly) with signal processing methods (PSD analysis of position error signals). The read element detects position errors during normal operation, and computational algorithms (PSD analysis, peak detection, statistical testing) identify contamination without physical intervention, thus resolving the contradiction between detection accuracy and device complexity
Solution Approach 2:
The patent introduces position error signals as an intermediary carrier that conveys contamination information. Instead of directly observing the contaminant physically, the system uses the modulated position error signals generated by the contaminant's interaction with the air bearing surface as an intermediary measurement, allowing indirect non-intrusive detection
2Measurement precision
If physical disassembly is performed for contamination detection, then detection capability is improved, but time consumption increases and productivity decreases
Solution Approach 1:
The system uses the device's own operational signals (position error signals generated during normal read operations) for self-diagnostics. The contaminant itself generates the detection signal through its interaction with the air bearing surface, eliminating the need for external inspection equipment and physical disassembly, thus dramatically improving productivity while maintaining detection capability
Solution Approach 2:
The patent enables continuous monitoring of slider contamination during normal device operation. Position error signals are continuously generated during read operations, and the PSD analysis can be performed continuously or at scheduled intervals, providing ongoing detection without interrupting device functionality or requiring periodic disassembly, thus maintaining high productivity
3Measurement precision
If invasive physical inspection methods are used, then detection accuracy is improved, but reliability of the detection system decreases due to destructive nature
Solution Approach 1:
The patent substitutes destructive mechanical inspection with non-intrusive signal analysis. By using PSD analysis of position error signals generated during normal operation, the system achieves accurate contamination detection without physical contact or disassembly, thereby maintaining both high detection accuracy and system reliability
Solution Approach 2:
The patent creates a virtual copy of the contamination state through signal processing. Instead of physically examining the contaminant, the system analyzes the modulated position error signals that encode contamination information, creating a digital representation (PSD waveform, peak values) that can be analyzed repeatedly without affecting the physical slider or medium
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
Enables efficient, non-destructive, and non-intrusive detection of slider contamination, allowing for accurate identification of contamination presence and type without disassembling the device, improving quality control and reliability of data storage devices.
Implementation Method 1
The slider has an air bearing surface adapted to interact with fluidic currents established by rotation of the medium to hydrodynamically support the read element adjacent the medium
Data Source
AI summary
Apparatus and method for non-destructive detection of contamination on a slider in a data storage device. In some embodiments, the slider supports a read element adjacent a rotating data recording medium. A non-repeatable runout (NRRO) component of a position error signal (PES) obtained from readback signals transduced from the read element is extracted. A power spectral density (PSD) analysis of the NRRO component is performed to identify a peak power level, and slider contamination is detected responsive to the peak power level.