Heat-Assisted Magnetic Recording Head Plasmon Generator Design
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Solution Overview
Problem
Heat-assisted magnetic recording heads face challenges in efficiently generating near-field light with a small spot diameter due to low light transformation efficiency and temperature-related issues with traditional plasmon antennas, which affect recording density and data writing accuracy.
Innovation Solution
A heat-assisted magnetic recording head design featuring a plasmon generator with a shape-changing portion where the angle of inclination of inclined surfaces increases continuously towards the medium facing surface, coupled with a waveguide and a magnetic pole, to efficiently transform light into near-field light with a small spot diameter, preventing excessive temperature rise and maintaining optimal head positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a plasmon antenna is used to generate near-field light by direct irradiation with light, then near-field light can be generated, but the transformation efficiency of light into near-field light is very low and the plasmon antenna temperature increases significantly
Solution Approach 1:
The patent introduces a waveguide as an intermediary component between the light source and the plasmon generator. The waveguide guides light to the plasmon generator, enabling efficient energy transfer while preventing direct irradiation of the plasmon generator with high-intensity light, thus reducing temperature increase and improving transformation efficiency.
Solution Approach 2:
The patent replaces the conventional direct light irradiation method with a waveguide-based light guidance system. This substitution allows for controlled and efficient light delivery to the plasmon generator, improving the transformation efficiency of light into near-field light while reducing unwanted thermal effects.
2Illumination intensity
If the plasmon antenna absorbs thermal energy, then near-field light is generated, but the plasmon antenna expands in volume and protrudes from the medium facing surface
Solution Approach 1:
The waveguide acts as a mediator that delivers light energy to the plasmon generator in a controlled manner, reducing excessive thermal absorption that would cause expansion and shape distortion. This maintains the plasmon generator's shape stability while still enabling near-field light generation.
Solution Approach 2:
The patent changes the operational parameters by using a waveguide to control the intensity and distribution of light reaching the plasmon generator. This parameter control prevents excessive temperature rise and associated thermal expansion, maintaining the structural integrity and shape stability of the plasmon generator.
3Temperature
If the read head gets farther from the magnetic recording medium due to plasmon antenna expansion, then thermal issues are reduced, but servo signal reading capability is lost
Solution Approach 1:
The waveguide serves as an intermediary that enables efficient light delivery to the plasmon generator without requiring direct high-intensity irradiation. This reduces thermal expansion of the plasmon generator, maintaining its position and ensuring continuous, precise servo signal reading capability.
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 solution enables high-efficiency light use and near-field light generation with a small spot diameter, enhancing recording density and preventing thermal expansion issues, thus improving data writing accuracy and head stability.
Implementation Method 1
the core has an evanescent light generating surface that generates evanescent light based on light propagated through the core
Implementation Method 2
surface plasmons are excited on the plasmon exciting part through coupling with the evanescent light generated from the evanescent light generating surface
Implementation Method 3
the near-field light generating part generates near-field light based on the surface plasmon excited on the plasmon exciting part
Data Source
AI summary
A plasmon generator has an outer surface including a plasmon exciting part, and has a near-field light generating part located in a medium facing surface. The plasmon exciting part faces an evanescent light generating surface of a waveguide's core with a predetermined distance therebetween. The outer surface of the plasmon generator further includes first and second inclined surfaces that are each connected to the plasmon exciting part. The first and second inclined surfaces increase in distance from each other with increasing distance from the plasmon exciting part. The plasmon generator includes a shape changing portion where the angle of inclination of each of the first and second inclined surfaces with respect to the evanescent light generating surface increases continuously with decreasing distance to the medium facing surface.