Solid Immersion Mirror with Fill Material for HAMR NFT Protection

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Solution Overview

Problem

Heat-assisted magnetic recording (HAMR) devices face challenges due to localized thermal protrusions of near-field transducers (NFTs) which can lead to damage and inaccurate contact detection, limiting device reliability and areal data density.

Innovation Solution

A solid immersion mirror with parabolic, reflective sidewalls and a fill material between the inner and outer sidewalls is used to focus light onto the NFT, reducing thermal protrusions and elevating a bumper or landing pad to shelter the NFT, thereby controlling temperature and mechanical contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If light is focused onto the near-field transducer to enable heat-assisted magnetic recording, then the heating capability is improved, but thermal protrusions damage the transducer and reduce reliability

Engineering Contradiction:

Improveheating capabilityVSAvoidtransducer reliability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

A bumper structure is positioned between the near-field transducer and the recording medium to absorb mechanical contact forces before they reach the transducer. This cushioning element prevents direct contact damage while allowing the transducer to operate at high power levels for heating the magnetic medium.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The invention introduces a vertical dimension to the problem by elevating the near-field transducer above the recording medium surface using a support structure. This dimensional separation allows the transducer to maintain a controlled distance from the medium, preventing thermal protrusion damage while preserving optical coupling for heating.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Productivity

If the near-field transducer is positioned close to the recording medium for effective heating, then the heating efficiency is improved, but thermal protrusions cause inaccurate contact detection

Engineering Contradiction:

Improveheating efficiencyVSAvoidcontact detection accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

A dedicated bumper structure serves as an intermediary element between the near-field transducer and the recording medium. This mediator provides a known mechanical reference point for contact detection, allowing the system to distinguish between bumper contact (normal operation) and transducer contact (abnormal condition), thereby improving measurement precision.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If the thermal protrusion area is small for precise data writing, then the data density is improved, but the transducer is more susceptible to damage

Engineering Contradiction:

Improvedata writing precisionVSAvoidtransducer damage risk

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The bumper structure provides beforehand cushioning by being positioned to contact the recording medium before the near-field transducer can be damaged by thermal protrusions. This allows the system to operate with small thermal protrusion areas for precise data writing while protecting the transducer from mechanical damage.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 configuration reduces the area of thermal protrusion from less than 0.01 μm² to greater than 10 μm², enhancing device reliability by distributing contact impact and reducing wear on the NFT, thus improving data storage capabilities.

Implementation Method 1

A solid immersion mirror with parabolic, reflective sidewalls and a fill material between the inner and outer sidewalls is used to focus light onto the NFT

Methodology Applied

Scientific EffectLight focusing: Focusing

Implementation Method 2

opposing, reflective, inner sidewalls having inner surfaces facing a focal region

Methodology Applied

Scientific EffectLight reflection: Reflection

Implementation Method 3

Heat-assisted magnetic recording (HAMR) devices face challenges due to localized thermal protrusions of near-field transducers (NFTs)

Methodology Applied

Scientific EffectOptical heating: Heating

Implementation Method 4

a fill material between the inner sidewalls and outer sidewalls... reducing thermal protrusions

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS9070385B2Solid immersion mirror with fill material between inner and outer sidewalls

Publication Date: 2015.06.30 SEAGATE TECH LLC

AI summary

An apparatus includes a solid immersion mirror with opposing, reflective, inner sidewalls having inner surfaces facing a focal region and outer surfaces opposite the inner surfaces. The solid immersion mirror also include opposing outer sidewalls spaced apart from and facing the outer surfaces of the inner sidewalls, and a fill material between the inner sidewalls and outer sidewalls. The apparatus also includes a near-field transducer located in the focal region proximate a media-facing surface.