HAMR Read/Write Head Reversed Configuration
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Solution Overview
Problem
In heat-assisted magnetic recording (HAMR) disk drives, the write pole tip protrusion during writing can lead to an undesirable high minimum fly-height design, and high heater power is required for read head protrusion, affecting efficiency and longevity.
Innovation Solution
Reversing the locations of the read head and write head on the slider reduces write pole tip protrusion and improves heat dissipation, allowing for a more efficient heater operation with reduced power consumption and lower design minimum fly-height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the write head is located closer to the disk surface, then writing performance is improved, but write pole tip protrusion increases leading to higher minimum fly-height design
Solution Approach 1:
The patent inverts the conventional arrangement by placing the read head closer to the disk surface and the write head farther away. This reversal reduces write pole tip protrusion by 16% while maintaining writing performance, as the write head's thermal fly-height control brings it to the optimal position during writing operations without excessive protrusion
2Manufacturing precision
If heater power is increased to achieve read head protrusion, then read head positioning is improved, but energy consumption and heater temperature increase reducing efficiency and longevity
Solution Approach 1:
The patent introduces thermal fly-height control as an intermediary mechanism that uses a heater to thermally expand the slider body, indirectly positioning the read head. This mediator approach achieves precise read head positioning with 51% improved heater efficiency by controlling thermal expansion rather than directly actuating the read head
Solution Approach 2:
The patent utilizes thermal expansion of the slider body through controlled heating to achieve read head protrusion. By heating the slider material, which has a known coefficient of thermal expansion, the read head is positioned closer to the disk surface without requiring excessive heater power, thereby improving efficiency and reducing thermal stress on components
3Productivity
If write head is positioned closer to disk, then writing efficiency is improved, but heat dissipation becomes difficult increasing write pole tip protrusion
Solution Approach 1:
By inverting the head arrangement, the write head is positioned farther from the disk surface, creating additional space for heat dissipation pathways. This spatial separation allows heat to dissipate more effectively from the write head while maintaining writing efficiency through thermal fly-height control that optimizes the write head's distance from the disk during writing operations
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 configuration results in a 16% reduction in write pole tip protrusion and a 51% improvement in heater efficiency, leading to extended reader lifetime and reduced read sensor temperature.
Implementation Method 1
Joule heating of the heater causes the head to expand and thus move closer to the disk surface
Implementation Method 2
light from a laser diode is coupled to a waveguide that guides the light to a near-field transducer (NFT)
Data Source
AI summary
A heat-assisted magnetic recording (HAMR) disk drive read/write head has the write head located adjacent the trailing surface of the gas-bearing slider with the read head located adjacent the write head, which is the reversed location from conventional read/write heads. This results in reduced write head protrusion during writing which allows for a reduced minimum fly-height for the slider. For a HAMR read/write head that uses a heater to protrude the read head closer to the disk during reading, the reversed location allows for better heater efficiency and thus reduced heater power.