Variable Track Width HAMR Writing via Dynamic Laser Power Control
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Solution Overview
Problem
Current storage devices face challenges in increasing areal density capacity due to high bit error rates and adjacent track interference, which limits the ability to enhance tracks per inch and bits per inch beyond current limits without compromising performance.
Innovation Solution
The implementation of a heat-assisted magnetic recording (HAMR) system that dynamically alters the heat source power level of a HAMR head when writing to data tracks, allowing for varying track widths and overlaps to optimize areal density capacity by increasing linear density while maintaining an acceptable bit error rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If TPI and BPI values are increased to achieve high areal density capacity, then storage capacity is improved, but bit error rate increases and reading accuracy deteriorates
Solution Approach 1:
The patent changes the physical state of the magnetic medium by heating it temporarily during writing using a laser, which reduces the coercivity of the magnetic material. This allows data to be written at higher densities with better precision, thereby increasing areal density capacity while maintaining acceptable bit error rates through controlled thermal assistance during the writing process
2Quantity of substance
If TPI and BPI values are increased beyond current limits, then areal density capacity is improved, but reading accuracy and performance suffer
Solution Approach 1:
The patent temporarily changes the temperature parameter of the magnetic medium during writing by applying laser heat, which reduces coercivity and enables more precise magnetic domain formation. This allows tracks to be written at higher densities with better-defined boundaries, improving reading accuracy even at increased TPI and BPI values
3Quantity of substance
If heat source power is increased to write to overlapping tracks, then areal density capacity is improved, but adjacent track interference increases
Solution Approach 1:
The patent dynamically adjusts the laser power and track overlap parameters during the writing process. By controlling the degree of overlap and the timing of writes to adjacent tracks, the system allows tracks to be written with variable widths that minimize interference while maximizing areal density. The dynamic control ensures that heat diffusion does not cause excessive interference with adjacent tracks
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 enhances areal density capacity by efficiently managing track pitch, overlap, and size through intelligent manipulation of HAMR head laser power, reducing bit error rates and adjacent track interference, thereby increasing the number of tracks per inch without sacrificing performance.
Implementation Method 1
a heat source (e.g., a laser)
Implementation Method 2
heat-assisted magnetic recording (HAMR) system that dynamically alters the heat source power level
Implementation Method 3
write data to a band of consecutive data tracks
Data Source
AI summary
A storage device includes a storage controller configured to operate a heat-assisted magnetic recording head to write data to a band of consecutive data tracks in a consecutive track order while selectively alternating a power level of the heat source when writing to some data tracks of the band.