Near-field light generating device with incomplete oxidation adhesion layer

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Solution Overview

Problem

Existing near-field light generating devices for heat-assisted magnetic recording face challenges with exfoliation of the near-field light generating element and a significant drop in light use efficiency due to the adhesion layer, which affects the performance of the magnetic recording head and recording medium.

Innovation Solution

A near-field light generating device with a waveguide, a buffer layer, and an adhesion layer formed by incompletely oxidizing a metal layer, which enhances the adhesive strength and maintains light use efficiency by preventing exfoliation and optimizing surface plasmon polariton coupling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a metal adhesion layer is formed between the waveguide and the near-field light generating element, then adhesive strength is improved, but light use efficiency significantly drops

Engineering Contradiction:

Improveadhesive strengthVSAvoidlight use efficiency

Core Design Contradiction:

StrengthVSUse of energy by moving object

Solution Approach 1:

The patent changes the physical and chemical parameters of the adhesion layer by using incomplete oxidation to create a multi-layer structure with varying oxidation states. This allows the layer to simultaneously provide mechanical adhesion and optical transparency, resolving the contradiction between strength and light efficiency

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The adhesion layer is formed as a composite material containing metal, metal oxide, and oxygen-deficient metal oxide phases. This composite structure combines the adhesive properties of metal oxides with the optical properties of metal, achieving both strong adhesion and high light use efficiency

Inventive Principle:

Principle #40Composite materials

2Power

If the near-field light generating element is directly irradiated with light, then near-field light generation is achieved, but temperature increases significantly causing expansion and protrusion

Engineering Contradiction:

Improvenear-field light generationVSAvoidtemperature increase

Core Design Contradiction:

PowerVSTemperature

Solution Approach 1:

The patent introduces a buffer layer as an intermediary between the waveguide and the near-field light generating element. This buffer layer couples light through surface plasmon polaritons, enabling near-field light generation while preventing direct irradiation and the associated temperature increase

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct optical irradiation with a surface plasmon polariton coupling mechanism. This substitution allows energy transfer to generate near-field light without the thermal effects of direct light absorption, solving the temperature control problem

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 effectively prevents exfoliation of the near-field light generating element and maintains high light use efficiency, ensuring stable operation and improved recording performance in heat-assisted magnetic recording systems.

Implementation Method 1

the light propagating through the waveguide is totally reflected at the interface between the waveguide and the buffer layer to generate evanescent light permeating into the buffer layer

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

the evanescent light and collective oscillations of charges on the near-field light generating element, i.e., surface plasmons, are coupled with each other to excite the surface plasmons on the near-field light generating element

Methodology Applied

Scientific EffectSurface plasmon polariton coupling:

Implementation Method 3

generate evanescent light permeating into the buffer layer

Methodology Applied

Scientific EffectEvanescent light:

Implementation Method 4

an adhesion layer which is formed by incompletely oxidizing a metal layer

Methodology Applied

Scientific EffectIncomplete oxidation: Oxidation

Data Source

PatentUS8040761B2Near-field light generating device including near-field light generating element disposed over waveguide with buffer layer and adhesion layer therebetween

Publication Date: 2011.10.18 TDK CORP

AI summary

A near-field light generating device includes: a waveguide; a buffer layer disposed on the top surface of the waveguide; an adhesion layer that is formed by incompletely oxidizing a metal layer and disposed on the buffer layer; and a near-field light generating element disposed on the adhesion layer. The adhesion layer has a resistance-area product higher than that of the metal layer unoxidized and lower than that of a layer that is formed by completely oxidizing the metal layer. A layered structure consisting of the buffer layer, the adhesion layer and the near-field light generating element has a peel-test adhesive strength higher than that of a layered structure consisting of the buffer layer and the near-field light generating element.