TAR Head Conductive Layer Between NFT and Write Pole

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Solution Overview

Problem

Conventional thermally-assisted recording (TAR) systems require high laser power and can suffer from undesirable thermal protrusion and damage due to excessive temperature rise in the near-field transducer (NFT), which affects the efficiency and reliability of data recording.

Innovation Solution

The introduction of an electrically conductive layer between the NFT and the write pole, with a triangular output tip and a recessed contact edge, reduces laser power requirements and mitigates temperature rise by acting as a heat sink, thereby enhancing optical near-field intensity and preventing thermal damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high laser power is used to heat the recording material in TAR systems, then the recording efficiency is improved, but the temperature rise in the near-field transducer causes thermal protrusion and possible damage

Engineering Contradiction:

Improverecording efficiencyVSAvoidNFT thermal stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

A conductive layer is introduced as an intermediary component between the NFT and write pole. This intermediate structure serves as a thermal management interface that facilitates controlled heat dissipation from the NFT while maintaining the necessary optical and magnetic field interactions for TAR operation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the thermal parameters of the TAR head by incorporating a conductive layer with specific thermal conductivity properties. This changes the heat transfer characteristics, allowing for reduced laser power operation while maintaining effective recording through optimized thermal management of the NFT

Inventive Principle:

Principle #35Parameter changes

2Illumination intensity

If the NFT is positioned close to the write pole for effective near-field coupling, then the optical near-field intensity is improved, but the thermal protrusion of the NFT increases

Engineering Contradiction:

Improveoptical near-field intensityVSAvoidNFT temperature

Core Design Contradiction:

Illumination intensityVSTemperature

Solution Approach 1:

The conductive layer acts as a thermal intermediary that decouples the thermal and optical functions. It allows the NFT to maintain its optimal position for near-field coupling while providing a dedicated thermal management path that prevents heat accumulation in the NFT structure

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The thermal management function is extracted from the NFT structure itself and assigned to a separate conductive layer. This separation allows the NFT to focus on generating the optical near-field while the conductive layer handles the thermal dissipation, preventing thermal protrusion

Inventive Principle:

Principle #2Taking out (Extraction)

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 necessary laser power, enhances optical near-field intensity, and prevents thermal protrusion, improving the efficiency and reliability of data recording while minimizing potential damage to the NFT.

Implementation Method 1

a near-field transducer (NFT)...an evanescent wave generated at a surface of the waveguide couples to surface plasmons excited on the surface of the NFT and a strong optical near-field is generated

Methodology Applied

Scientific EffectOptical near-field generation: Absorption (EM radiation)

Implementation Method 2

an electrically conductive layer between and in contact with the NFT and the write pole...reduces the temperature rise of the NFT, which can cause undesirable thermal protrusion of the NFT

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS8619516B1Thermally-assisted recording (TAR) head with conductive layer between the near-field transducer and the write pole

Publication Date: 2013.12.31 WESTERN DIGITAL TECHNOLOGIES INC

AI summary

A thermally-assisted recording (TAR) head for recording data in data tracks of a TAR disk is supported on an air-bearing slider and includes the magnetic write pole, a near-field transducer (NFT), an optical waveguide that directs laser light to the NFT, and an electrically conductive layer between and in contact with the NFT and the write pole. The NFT has an output tip having a generally triangularly-shaped end at the slider's air-baring surface (ABS). The electrically conductive layer is located between the NFT and the write pole and contacts both the NFT output tip and the write pole. The electrically conductive layer has a contact edge that is generally parallel with the ABS but recessed from the NFT output tip end and a cross-track width greater than the cross-track width of the NFT output tip end.