Curved Waveguide for Miniaturized Thermal Assisted Magnetic Recording
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Solution Overview
Problem
Conventional magnetic recording technologies face challenges in increasing recording density due to the thermal stability of magnetic micro particles and the difficulty in incorporating a laser diode with a curved waveguide into a magnetic head slider, which requires a curvature radius of 10 μm or less for miniaturization.
Innovation Solution
A curved waveguide with a core and outside metal cladding that propagates laser light as propagating light, featuring a core with planar surfaces and curved surfaces, and a cladding layer to minimize propagating loss, integrated into a thermally assisted magnetic recording system with a plasmon generator and main pole for near-field light generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional straight waveguide is used to propagate laser light from the laser diode to the plasmon generator, then the structure is simple and easy to manufacture, but the laser diode cannot be incorporated within the magnetic head slider due to space constraints and the required curvature radius is too large for miniaturization
Solution Approach 1:
The waveguide core is designed with a curved configuration instead of a straight path, allowing the laser light to be guided around the bend with a small curvature radius (10 μm or less) while maintaining low propagating loss. The curved core enables the laser diode to be positioned within the magnetic head slider assembly, achieving miniaturization and integration.
2Quantity of substance
If the magnetic micro particles are decreased in size to enhance recording density, then the recording density increases, but the thermal stability of magnetization of the magnetic micro particles is reduced
Solution Approach 1:
The patent changes the physical state and properties of the magnetic recording medium by applying heat locally to reduce the coercive force, enabling recording on media with high anisotropic energy that would otherwise be difficult to record. This parameter change (temperature) allows the system to achieve both high recording density and thermal stability.
3Stability of the object's composition
If the anisotropic energy of the magnetic micro particles is increased to improve thermal stability, then the thermal stability improves, but the coercive force becomes great and it becomes difficult to record information by the existing magnetic head
Solution Approach 1:
The patent employs periodic or pulsed application of heat and magnetic field to the recording medium. The laser diode emits laser light that is modulated to heat specific regions periodically, and the magnetic field is applied in synchronization with the heating cycles, enabling successful recording on high-coercivity media by temporarily reducing the coercive force during the recording process.
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 reduced curvature radius and minimized propagating loss, allowing for efficient propagation of laser light and near-field generation, enhancing recording density and reliability in magnetic recording systems.
Implementation Method 1
a curved waveguide with a core and outside metal cladding that propagates laser light as propagating light
Implementation Method 2
outside metal cladding that is positioned in a direction orthogonal to an oscillation direction of an electric field of the propagating light
Implementation Method 3
plasmon generator that extends to an air bearing surface as facing a part of the waveguide and that generates the near field light on the air bearing surface
Implementation Method 4
when recording information, a magnetic field and heat are simultaneously applied to a part of the magnetic recording medium where information is recorded. This causes a rise in temperature in the part where the information is recorded and a reduction of the coercive force
Data Source
AI summary
A curved waveguide is a curved waveguide that propagates laser light entering from the laser diode as propagating light. The curved waveguide includes a core that is curved in one direction where the propagating light can be propagated and that includes outer surfaces along a propagating direction of the propagating light defined by four surfaces including first and second planar surfaces that curve in respective planar surfaces and that are positioned to face each other, and inside and outside curved surfaces that connect the first and second planar surfaces: an outside metal cladding that is positioned in a direction orthogonal to an oscillation direction of an electric field of the propagating light in a cross section orthogonal to the propagating direction of the propagating light and along the outside curved surface of the core, that is made of gold, silver, copper or aluminum, or that is primarily composed of one component of these materials; and a cladding layer that covers the first and second planar surfaces and the outside metal clad.