Slider Sensor Signal Segmentation for Head Flying Height Control
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Solution Overview
Problem
Current disk drives face challenges in accurately detecting touch-down and contact states between the head and storage medium, which affects flying height adjustment and overall performance, especially with increasing density and compactness.
Innovation Solution
A method and apparatus using a sensor installed in the slider to separate DC and AC components of a signal, where the DC component is used for touch-down detection during a test and the AC component for contact detection in an operating state, with the sensor's resistance changing with temperature, allowing for precise flying height control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor signal is used to detect touch-down and contact states, then measurement precision is improved, but device complexity increases due to signal processing requirements
Solution Approach 1:
The sensor signal is segmented into DC and AC components using separate processing paths. The DC component processing path includes a DC extractor and threshold comparator for touch-down detection, while the AC component processing path includes an AC extractor and threshold comparator for contact detection. This segmentation allows each component to be processed independently with dedicated circuitry, improving detection accuracy while managing system complexity through modular design.
2Measurement precision
If DC and AC components are separated for different detection purposes, then measurement precision is improved, but device complexity increases due to additional processing circuits
Solution Approach 1:
The signal processing system is divided into two independent segmentation paths: a DC component processing path for touch-down detection and an AC component processing path for contact detection. Each path has dedicated extraction circuits and threshold comparators, allowing precise detection of different head states while maintaining modular circuit design that manages overall system complexity.
Solution Approach 2:
The sensor serves multiple functions by providing both DC and AC signal components that are processed separately. The same physical sensor detects both touch-down events (via DC component) and contact events (via AC component), eliminating the need for separate sensors and reducing overall device complexity despite the dual processing paths.
3Productivity
If the head flying height is adjusted for higher density storage, then productivity is improved, but reliability worsens due to increased risk of head-storage medium contact
Solution Approach 1:
The system implements feedback control by continuously monitoring the sensor signal and comparing DC and AC components against predetermined thresholds. When the DC component exceeds its threshold (indicating touch-down) or the AC component exceeds its threshold (indicating contact), the system generates alerts and can adjust the head flying height accordingly. This feedback mechanism enables safe operation at reduced flying heights for higher density storage while preventing harmful head-storage medium contact.
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 accurate detection of touch-down and contact states, allowing for optimal flying height adjustment and improved performance by effectively separating and processing signal components, enhancing the operational efficiency of disk drives.
Implementation Method 1
a sensor installed in a slider to separate DC and AC components of a signal, where the DC component is used for touch-down detection during a test and the AC component for contact detection in an operating state, with the sensor's resistance changing with temperature
Data Source
AI summary
A method and apparatus for detecting a touch-down and contact between a head and a storage medium by using a signal generated by a data storage device, specifically by a sensor installed in a slider. The method includes: separating a signal detected by a sensor into a direct current (DC) component and an alternating current (AC) component, wherein the sensor has an electrical characteristic that changes according to temperature; using the DC component to detect a touch-down state of the head during a touch-down test to determine a value of a control signal for adjusting the flying height of the head; and using the AC component to detect a contacting state between the head and the storage medium in an operating state of the apparatus.