Hard Disk Drive Head with Thermal Expansion Flying Height Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetic disk drives face challenges in maintaining reliable writing operations at high frequencies due to reduced flying height caused by heating of the write head, leading to potential contact with the disk medium and degraded signal quality, especially in the circumferential direction.
Innovation Solution
A hard disk drive system that includes a magnetic head with a detection circuit to monitor drive current conditions during writing, utilizing an energy conversion element such as a thermal expansion element and a spin-torque oscillator to control flying height and generate a high harmonic magnetic field, thereby assisting the magnetic head during writing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the write head operates at high frequency, then data recording speed is improved, but the flying height decreases due to thermal expansion causing head contact with the disk medium
Solution Approach 1:
The patent applies preliminary action by detecting the recording condition (frequency) in advance and proactively adjusting the flying height before head contact occurs. The flying height control circuit receives the frequency signal and adjusts the thermal expansion element to maintain optimal flying height at high frequencies, preventing harmful contact before it happens.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the recording frequency and using this information to dynamically adjust the flying height. The frequency detection circuit provides real-time feedback to the flying height control circuit, which then adjusts the thermal expansion element to maintain stable flying height despite frequency changes.
2Measurement precision
If the write head generates stronger magnetic field for high frequency writing, then signal quality is improved, but thermal expansion increases causing head contact with the disk medium
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the flying height parameter in response to frequency changes. When frequency increases requiring stronger magnetic field, the system simultaneously adjusts the flying height parameter through thermal expansion control to maintain safe clearance, thus allowing strong magnetic field operation without head contact.
Solution Approach 2:
The system performs preliminary adjustment of flying height before head contact can occur. By detecting frequency increases that would lead to thermal expansion and potential contact, the system proactively adjusts the flying height to maintain safe clearance while allowing the stronger magnetic field needed for high-frequency writing.
3Reliability
If thermal expansion element is used to control flying height, then flying height stability is improved, but write magnetic field strength is reduced
Solution Approach 1:
The patent applies dynamics by making the flying height control adaptive rather than static. The thermal expansion element is dynamically adjusted based on real-time frequency detection, allowing the system to optimize both flying height stability and magnetic field strength for each operating condition, rather than using a fixed control approach.
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 solution enhances signal quality and reduces data loss by maintaining optimal flying height and magnetic field strength, even at high frequencies, while minimizing contact with the disk medium and improving reliability.
Implementation Method 1
a thermal expansion element adapted for controlling a flying height distance between the magnetic head and the magnetic disk medium, wherein the thermal expansion element causes expansion of a portion of the magnetic head due to heat produced by the thermal expansion element
Implementation Method 2
a spin-torque oscillator (STO) adapted for assisting the magnetic head during writing operations by generating a high harmonic magnetic field from an external magnetic field produced by applying current to the STO
Data Source
AI summary
In one embodiment, a hard disk drive includes a magnetic disk medium, a magnetic head adapted for writing data to the magnetic disk medium, a mechanism (such as a detection circuit) adapted for detecting at least one recording condition of drive current provided to the magnetic head during writing operations, and an energy conversion element for controlling at least one recording characteristic of the magnetic head in response to the at least one detected recording condition. According to another embodiment, a method includes writing data to a magnetic medium using a magnetic head, detecting at least one recording condition of drive current provided to the magnetic head during the writing, and controlling at least one recording characteristic of the magnetic head during the writing using an energy conversion element in response to the at least one detected recording condition.