Slider Interface Voltage Control for Safe Fly Height
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Solution Overview
Problem
Conventional data storage devices face issues with slider-disk contact and lubricant accumulation due to unbalanced electrostatic forces, which degrade the performance and lifespan of sliders, particularly in Energy-Assisted Magnetic Recording technologies.
Innovation Solution
Applying an Interface Voltage Control (IVC) to maintain a target offset voltage between the slider and disk by using a voltage less than the disk voltage, thereby passivating the slider and reducing electrostatic attraction, thus protecting it from mechanical wear and oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If IVC is applied to passivate the slider by encapsulating it with static electrical charge, then the slider life and protection from mechanical wear and chemical oxidation are improved, but the slider-disk electric potential difference may not be completely cancelled, causing attractive electrostatic force that pulls the slider towards the disk
Solution Approach 1:
The patent applies IVC by changing the electrical parameter (voltage) applied to the slider. A voltage less than the disk voltage is applied to the slider body to provide passivation while controlling the electrostatic attraction. This parameter change allows the system to achieve both slider protection and acceptable fly height maintenance.
2Object-affected harmful factors
If a voltage less than the disk voltage is applied to the slider to maintain target offset voltage, then the electrostatic attraction is reduced and slider protection is enhanced, but the fly height may be affected by the remaining attractive force
Solution Approach 1:
The patent employs feedback control by monitoring the fly height and adjusting the IVC voltage accordingly. The system maintains a target offset voltage between the slider and disk by using feedback from fly height measurements to control the voltage applied to the slider, thereby balancing passivation benefits with fly height maintenance.
3Object-affected harmful factors
If conventional IVC is used to cancel the slider-disk electric potential difference completely, then the attractive electrostatic force is minimized, but the slider is not adequately protected from mechanical wear and chemical oxidation
Solution Approach 1:
The patent inverts the conventional IVC approach by not completely cancelling the electric potential difference. Instead of making the slider voltage equal to the disk voltage to eliminate attraction, the patent applies a voltage less than the disk voltage to maintain a controlled offset, achieving both reduced attraction and adequate passivation protection.
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 usable life of sliders and their components by maintaining a safe fly height and reducing contact risks, enhancing the durability of advanced magnetic recording technologies like HAMR, MAMR, and ePMR.
Implementation Method 1
The slider has a disk-facing Gas-Bearing Surface (GBS) that causes the slider to ride on a cushion or bearing of gas, typically air or helium, generated by rotation of the disk.
Implementation Method 2
The slider is attached to a flexure on the suspension and the suspension includes a load beam that applies a load force to the slider to counteract the gas-bearing force
Implementation Method 3
IVC may be used to passivate the slider by encapsulating at least a portion of the slider body with a static electrical charge, which can help preserve the life of the slider and its components by protecting it from mechanical wear, as well as from chemical oxidation.
Implementation Method 4
When the slider-disk electric potential difference is not cancelled completely, an attractive electrostatic force pulls the slider towards the disk
Data Source
AI summary
A Data Storage Device (DSD) comprises a magnetic disk and a slider including a writer configured to magnetically write data on the magnetic disk. A voltage is applied to the slider to provide a target offset voltage between the slider and the magnetic disk with the applied voltage differing from a disk voltage of the magnetic disk. In one aspect, a first disk voltage is determined for the magnetic disk. The voltage to be applied to the slider is determined to adjust an electric potential difference between the slider and the disk to the non-zero target offset voltage. In another aspect, the voltage applied to the slider is less than the disk voltage and reduces deterioration of the slider caused by operation of an energy-assisted magnetic recording technology at the slider while maintaining a safe fly height of the slider over the magnetic disk.