TAMR Antenna Preheating for Protrusion Transient Control
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Solution Overview
Problem
The rapid thermally induced protrusion of a plasmon antenna in dynamic fly height (DFH) thermally assisted magnetic recording (TAMR) read/write heads leads to head/disk interference due to the difference in response times between the antenna protrusion and the DFH mechanism, which cannot adequately compensate for the protrusion transient.
Innovation Solution
Slowly preheat the plasmon antenna to approximately 50% of its final temperature using a lower power laser before full power activation, allowing the DFH mechanism to compensate for the subsequent protrusion, reducing the transient and preventing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the plasmon antenna is rapidly heated to full power for TAMR operation, then the writing capability on high coercivity media is improved, but the transient protrusion causes head/disk interference
Solution Approach 1:
The patent applies preliminary action by preheating the plasmon antenna to a predetermined temperature (approximately 50% of final temperature) before activating full laser power for TAMR operation. This preliminary heating allows the DFH mechanism to compensate for thermal expansion in advance, preventing the transient protrusion that would otherwise cause head/disk interference when full power is suddenly applied.
2Speed
If the DFH mechanism responds quickly to compensate for antenna protrusion, then head/disk interference is reduced, but the response time is still insufficient to match the rapid antenna protrusion
Solution Approach 1:
The patent uses preliminary action to prepare the system in advance by heating the antenna to a predetermined temperature before full operation. This allows the DFH mechanism to gradually adjust and compensate for thermal expansion over time, matching its slower response characteristics and avoiding transient protrusion problems that would occur with sudden full-power activation.
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 significantly reduces the protrusion transient, minimizing head/disk interference while maintaining the ability to achieve high data densities without adverse effects on the magnetic medium, ensuring efficient and reliable operation of the read/write head.
Implementation Method 1
The source of optical excitement is a laser diode, also incorporated within the read/write head structure, which directs its beam at the antenna
Implementation Method 2
the rapid thermally induced protrusion of a plasmon antenna in dynamic fly height (DFH) thermally assisted magnetic recording (TAMR) read/write heads
Implementation Method 3
the difference in response times between the antenna protrusion and the DFH mechanism, which cannot adequately compensate for the protrusion transient
Data Source
AI summary
A slider mounted TAMR (Thermal Assisted Magnetic Recording), DFH (Dynamic Flying Height) type read/write head using optical-laser generated surface plasmons in a small antenna to locally heat a magnetic medium, uses the same optical laser at low power to pre-heat the antenna. Maintaining the antenna at this pre-heated temperature, approximately 50% of its highest temperature during write operations, allows the DFH mechanism sufficient time to compensate for the thermal protrusion of the antenna at that lower temperature, so that thermal protrusion transients are significantly reduced when a writing operation occurs and full laser power is applied. The time constant for antenna protrusion is less than the time constant for DFH fly height compensation, so, without pre-heating, the thermal protrusion of the antenna due to absorption of optical radiation cannot be compensated by the DFH effect.