V-Shaped Plasmon Generator for Heat Dissipation in TAMR Heads
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Solution Overview
Problem
In thermally assisted magnetic recording, the heat generated by near-field light in conventional plasmon generators accumulates, leading to protrusion issues and reduced optical-power efficiency, while reducing the thickness of the plasmon generator to improve heat dissipation causes degradation of the magnetic pole.
Innovation Solution
A thermally assisted magnetic head design featuring a plasmon generator with a V-shaped convex part that contacts the magnetic pole, where the thickness gradually increases from the waveguide end to the magnetic pole end, allowing heat to dissipate effectively without degrading the magnetic pole.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the thickness of the plasmon generator is reduced to improve heat dissipation, then heat dissipation is improved, but degradation of the magnetic pole is caused
Solution Approach 1:
The plasmon generator is designed with non-uniform thickness where the thickness varies in the light propagation direction. Specifically, the thickness is smaller at the incident light end and larger at the opposite end, creating local quality variations that optimize both heat dissipation and magnetic pole protection in different regions of the same component.
Solution Approach 2:
The invention addresses the heat dissipation problem by introducing a dimensional variation in the thickness of the plasmon generator along the light propagation direction. This dimensional change allows heat to dissipate more effectively through the increased thickness at the exit end while maintaining structural integrity and preventing magnetic pole degradation.
2Temperature
If the thickness of the plasmon generator is reduced to improve heat dissipation, then heat dissipation is improved, but optical-power efficiency significantly decreases
Solution Approach 1:
The plasmon generator employs local quality variation with different thicknesses at different positions along the light propagation direction. The thinner region at the incident end maintains optical-power efficiency by allowing effective light coupling, while the thicker region at the exit end improves heat dissipation, thus resolving the contradiction between these two performance parameters.
3Illumination intensity
If conventional plasmon generator design is used, then near-field light is generated, but heat accumulates at the near-field light generating portion
Solution Approach 1:
The invention solves the heat accumulation problem by varying the thickness of the plasmon generator in the dimension parallel to the light propagation direction. This dimensional variation creates a thickness gradient that facilitates heat dissipation from the near-field light generating portion while maintaining the necessary optical properties for near-field light generation.
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 design suppresses magnetic pole degradation by facilitating heat dissipation from the near-field light generating portion to the magnetic pole, maintaining high recording density and optical-power efficiency.
Implementation Method 1
generates near-field light from a near-field light generating end surface by coupling light from a waveguide in a surface plasmon mode
Implementation Method 2
the near-field light generated at a near-field light generating portion of the plasmon generator heats the magnetic recording medium so as to decrease the anisotropic magnetic field
Implementation Method 3
the thickness gradually increases from an end positioned closest to the waveguide on the convex part contacting sides in a direction away from the waveguide, allowing heat to dissipate effectively without degrading the magnetic pole
Data Source
AI summary
A thermally assisted magnetic head includes a magnetic pole that generates a writing magnetic field from an air bearing surface (ABS); a waveguide through which light propagates; and a plasmon generator generating near-field light from a near-field light generating end surface by coupling the light thereto in a surface plasmon mode. The magnetic pole includes a convex part protruding in a substantially V-shape along a light propagation direction of the waveguide. The plasmon generator includes a substantially V-shaped part contacting the convex part, and as seen from a side of the ABS, a thickness of the plasmon generator in a direction perpendicular to convex part contacting sides gradually increases from an end in a direction away from the waveguide, the convex part contacting sides being linear sides that form the substantially V-shaped part of the plasmon generator and contacting the convex part.