Fly Height Actuator for Variable Track Width in HAMR

Solution Overview

Problem

Existing magnetic recording technologies face challenges in writing tracks of different widths without impacting bit error rate (BER), particularly in heat-assisted magnetic recording (HAMR) where changes in laser power affect reliability and thermal stability.

Innovation Solution

Varying the head-to-media spacing (HMS) using a fly-height actuator to change track widths, allowing for the writing of narrower and wider tracks with minimal impact on BER, while maintaining constant laser power and adjusting write coil current to compensate for thermal and environmental changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If laser power is changed to write tracks of different widths in HAMR, then track width varies, but bit error rate increases and thermal stability deteriorates

Engineering Contradiction:

Improvetrack widthVSAvoidbit error rate

Core Design Contradiction:

Length of moving objectVSReliability

Solution Approach 1:

The patent changes the head-to-media spacing parameter instead of laser power to achieve different track widths. By adjusting the fly height to first nominal value for narrow tracks and second nominal value for wide tracks, the system achieves track width variation without changing laser power, thereby avoiding BER deterioration and maintaining thermal stability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The fly height actuator serves as an intermediary mechanism between the recording head and media. It mediates the track width control by physically adjusting the spacing between the write transducer and media surface, allowing track width variation without directly affecting the laser power or thermal properties of the HAMR system.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Length of moving object

If laser power is changed to write tracks of different widths in HAMR, then track width varies, but thermal stability deteriorates

Engineering Contradiction:

Improvetrack widthVSAvoidthermal stability

Core Design Contradiction:

Length of moving objectVSStability of the object's composition

Solution Approach 1:

The patent changes the head-to-media spacing parameter instead of laser power to achieve different track widths. By adjusting the fly height to first nominal value for narrow tracks and second nominal value for wide tracks, the system achieves track width variation without changing laser power, thereby avoiding BER deterioration and maintaining thermal stability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The fly height actuator serves as an intermediary mechanism between the recording head and media. It mediates the track width control by physically adjusting the spacing between the write transducer and media surface, allowing track width variation without directly affecting the laser power or thermal properties of the HAMR system.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If fly height is varied to write tracks of different widths, then track width options increase, but device complexity increases

Engineering Contradiction:

Improvetrack width optionsVSAvoidcontrol system complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The fly height actuator, already present in the recording head for focus control, is made multi-functional by using it for track width control as well. This eliminates the need for separate track width adjustment mechanisms, thereby achieving versatile track width options without proportionally increasing device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes the head-to-media spacing parameter instead of laser power to achieve different track widths. By adjusting the fly height to first nominal value for narrow tracks and second nominal value for wide tracks, the system achieves track width variation without changing laser power, thereby avoiding BER deterioration and maintaining thermal stability.

Inventive Principle:

Principle #35Parameter changes

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 approach provides a range of track width options with reduced BER penalties, ensuring reliable data storage by maintaining consistent laser power and adjusting write coil current to achieve desired track widths, even in HAMR systems.

Implementation Method 1

varying head-to-media spacing (HMS) of a recording head

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

writing tracks of different widths using a magnetic recording head

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS9830944B1Writing adjacent tracks with different widths by varying fly height of a recording head

Publication Date: 2017.11.28 SEAGATE TECH LLC

AI summary

First and second nominal head-to-media spacings of a magnetic recording head are determined that result in tracks being written to a magnetic recording medium at respective narrower and wider tracks widths. Three or more adjacent tracks of user data are written to the magnetic recording medium using one of the first and second nominal head-to-media spacings so that the adjacent tracks alternate between the narrower and wider track widths.