Heat-Assisted Magnetic Recording Head Flying Height Adjustment
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Solution Overview
Problem
The existing magnetic recording and reproducing devices face challenges in maintaining consistent write performance due to fluctuations in flying height, which are exacerbated by the generation of lubricant-cured material during heat-assisted magnetic recording. Additionally, the accuracy of adjusting the flying height for write heads is inferior to that of read heads, and there is a need for adaptive adjustments in response to temperature changes and monitored flying conditions.
Innovation Solution
A method and device for adjusting the flying height of a heat-assisted magnetic recording head by performing write operations at multiple positions on a magnetic disk, measuring error rates before and after each operation, calculating differences in error rates, and comparing these differences to determine changes in flying height. This allows for precise adjustment of the flying height to maintain optimal write performance across varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flying height is lowered to improve write performance, then the lubricant-cured material is scraped off, but the transmittance of laser increases and material acts as a layer improving transmission efficiency
Solution Approach 1:
The patent performs preliminary adjustment of the flying height before actual recording operations. By pre-adjusting the flying height to an optimal value and maintaining it through monitoring during seek operations, the system prevents lubricant-cured material accumulation before it can adversely affect recording performance, thereby resolving the contradiction between write performance and material accumulation.
Solution Approach 2:
The patent implements feedback control by monitoring the flying height during seek operations and adjusting it to maintain optimal values. This continuous monitoring and adjustment prevents the formation of lubricant-cured material layers that would otherwise degrade write performance, while allowing the system to operate at lower flying heights when needed for improved recording efficiency.
2Reliability
If the flying height is adjusted for write head, then write performance improves, but the accuracy of adjustment is inferior to read head adjustment
Solution Approach 1:
The patent employs feedback control mechanisms to monitor and adjust the flying height of the write head with high precision. By continuously monitoring the flying height during seek operations and making real-time adjustments, the system achieves accurate flying height control comparable to read head adjustment, thereby resolving the contradiction between write performance improvement and adjustment accuracy.
Solution Approach 2:
The patent performs preliminary flying height adjustment before recording operations begin. By pre-establishing the optimal flying height through accurate measurement and control mechanisms, the system ensures that subsequent writing operations benefit from precise positioning, overcoming the historical limitation of inferior adjustment accuracy for write heads.
3Productivity
If the flying height fluctuates when head moves between tracks, then write performance is degraded until lubricant-cured material is generated, but material generation cannot be prevented during recording
Solution Approach 1:
The patent performs preliminary adjustment of the flying height to an optimal value before recording operations begin. By pre-establishing the correct flying height and maintaining it through monitoring during seek operations, the system prevents write performance degradation that would otherwise occur when the head moves between tracks with different flying heights, while still allowing efficient recording to proceed.
Solution Approach 2:
The patent implements feedback control by monitoring the flying height during seek operations and adjusting it to maintain optimal values. This continuous feedback mechanism ensures that the flying height remains stable during track transitions, preventing the generation of lubricant-cured material layers that would degrade write performance, while maintaining high recording efficiency.
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 proposed solution enables accurate determination and adjustment of flying height, thereby maintaining consistent write performance and reducing errors across different radial positions and temperature conditions. This approach improves the reliability and efficiency of magnetic recording and reproducing devices.
Implementation Method 1
the temperature of a magnetic disk is raised for recording by laser
Implementation Method 2
the transmittance of the laser is increased and the material acts as a layer which improves a transmission efficiency of the laser
Data Source
AI summary
According to one embodiment, a method of adjusting a magnetic recording and reproducing device is a method of adjusting a magnetic recording and reproducing device incorporating a heat-assisted magnetic recording head and a magnetic disk, and the method includes performing a first write operation at a first position on a recording surface, measuring a first error rate at a second position different in radial position from the first position, performing a second write operation and then measuring a second error rate, obtaining a first difference between the first error rate and the second error rate, measuring a third error rate at the first position, performing a third write operation and then measuring a fourth error rate, calculating a second difference between the third error rate and the fourth error rate, comparing the first difference with the second difference and determining a change in flying height.