Thermally Assisted Magnetic Head Optical Waveguide Positioning
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Solution Overview
Problem
Thermally assisted magnetic recording faces challenges in achieving high-density writing due to the distance between the light emitting position from the optical waveguide and the magnetic pole end part, which affects the thermal stability and coercivity of the magnetic recording medium, leading to inefficient writing.
Innovation Solution
A thermally assisted magnetic head design where the main magnetic pole layer is positioned on the side where the light is deflected by the optical waveguide, and the magnetic pole end part projects to the deflected side, with the optical waveguide projecting beyond the magnetic pole end part on the medium-opposing surface, allowing for closer proximity of the light emitting position to the magnetic pole end part and reducing the risk of coercivity decrease.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the magnetic fine particles are made smaller to enhance recording density, then the recording density is improved, but the thermal stability in magnetization deteriorates
Solution Approach 1:
The patent changes the temperature parameter by applying thermal assistance to the magnetic recording medium during writing. By heating the medium locally, the coercivity is temporarily reduced, allowing writing of smaller bits with higher density while maintaining thermal stability through the controlled temperature increase during the writing process
2Quantity of substance
If the magnetic fine particles are made smaller to enhance recording density, then the recording density is improved, but the coercivity increases
Solution Approach 1:
The patent dynamically changes the coercivity parameter by applying thermal assistance during the writing process. The heating temporarily reduces the coercivity of the magnetic recording medium, enabling the magnetic head to write smaller bits with higher density without being limited by the increased coercivity of the smaller particles
3Productivity
If the distance between the light emitting position and the magnetic pole end part is reduced to improve thermal stability, then the thermal assistance efficiency is improved, but the risk of coercivity decrease in the magnetic pole end part increases
Solution Approach 1:
The patent applies local quality by positioning the optical waveguide to emit light specifically at the magnetic pole end part, creating a localized heating zone. This concentrated thermal assistance improves writing efficiency at the critical writing location while the overall structure maintains coercivity stability through controlled, localized heating rather than uniform heating
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 enables high-density writing by ensuring effective heating of the magnetic recording medium while minimizing the decrease in coercivity, allowing for favorable recording performance.
Implementation Method 1
an optical waveguide including a first layer and a second layer, adjacent to the first layer, having a refractive index higher than that of the first layer and deflecting thermally assisting light incident thereon into a laminating direction
Implementation Method 2
light emitted from a light-emitting device is introduced into the optical waveguide and then is let out from a light exit surface of the optical waveguide within the medium-opposing surface, so as to heat a magnetic recording medium locally
Implementation Method 3
the electromagnetic coil device applies a writing magnetic field to a local area of the magnetic recording medium having lowered the coercivity by the local heating, so as to perform writing
Data Source
AI summary
While an emitting position of light from an optical waveguide and a magnetic pole end part are made closer to each other, high-density writing onto a magnetic recording medium is realized.A thermally assisted magnetic head comprises a main magnetic pole layer having a magnetic pole end part exposed at a medium-opposing surface opposing a magnetic disk, and an optical waveguide for deflecting laser light incident thereon into a laminating direction. The main magnetic pole layer is positioned on a side where the light is deflected by the optical waveguide. The magnetic pole end part projects to the side where the light is deflected by the optical waveguide. The optical waveguide projects more than the magnetic pole end part on the medium-opposing surface side.