Magnetic Head Slider with Embossed Portions for Backflow Suppression

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Solution Overview

Problem

Conventional magnetic disk devices face issues with lubricant adhesion to the slider, leading to high-fly write states due to backflows, which are difficult to suppress using existing surface tension reduction methods.

Innovation Solution

The magnetic head features a slider with a negative-pressure cavity, embossed portions, and a specific geometry that reduces backflows by altering airflow patterns, including a leading step portion, side portions, a trailing step portion, and embossed portions, which are flush with the outlet-side end surface, to minimize lubricant adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a negative-pressure cavity is formed on the slider surface to prevent lubricant adhesion, then lubricant adhesion is reduced, but backflows still occur causing high-fly write states

Engineering Contradiction:

Improvelubricant adhesionVSAvoidwriting accuracy

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The slider surface is segmented into multiple functional regions: a negative-pressure cavity region for reducing lubricant adhesion, and a protruding portion region for suppressing backflows. This segmentation allows each region to address specific problems independently, preventing both lubricant adhesion and backflow-induced high-fly writes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the slider surface are given different geometric properties: the negative-pressure cavity has a specific depth and shape to create negative pressure and reduce lubricant adhesion, while the protruding portion has a height and position optimized to suppress backflows. This local differentiation of surface properties enables simultaneous resolution of both issues.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If conventional surface tension reduction methods are used to prevent lubricant adhesion, then lubricant adhesion is reduced, but backflows cause lubricant to adhere anyway

Engineering Contradiction:

Improvelubricant adhesionVSAvoidbackflows

Core Design Contradiction:

Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The protruding portion on the slider surface is strategically positioned to convert the harmful backflow phenomenon into a beneficial effect. By placing the protruding portion at the downstream end of the negative-pressure cavity, the backflow is redirected and suppressed, preventing lubricant from adhering to the slider despite the presence of backflows.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The protruding portion acts as an intermediary structure between the negative-pressure cavity and the ambient environment. It mediates the airflow and lubricant interaction, preventing direct contact between backflowing lubricant and the slider surface while maintaining the negative-pressure cavity's lubricant-repelling function.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If the slider flying height is increased to avoid disk contact, then disk abrasion is reduced, but the magnetic head floats above the disk surface causing high-fly write

Engineering Contradiction:

Improvedisk abrasionVSAvoidwriting accuracy

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The slider surface geometry parameters are precisely controlled: the negative-pressure cavity depth is set to 0.5-2.0 μm and the protruding portion height is set to 0.2-1.0 μm. These parameter optimizations ensure the slider maintains an appropriate flying height that prevents disk contact and abrasion while avoiding excessive floating that would cause high-fly write errors.

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 configuration effectively reduces backflows and lubricant adhesion, maintaining stable flying heights and improving the reliability and stability of the magnetic head, preventing the formation of protuberances on the disk surface.

Implementation Method 1

a negative-pressure cavity which produces a negative pressure

Methodology Applied

Scientific EffectNegative pressure: Pressure Drop

Implementation Method 2

Based on the principle of aerodynamic lubrication, a force (positive pressure) to fly the slider above the recording surface of the disk acts on the facing surface of the slider

Methodology Applied

Scientific EffectAerodynamic lubrication: Air Lubrication

Data Source

PatentUS8179638B2Head with slider suppressing back flow, head suspension assembly, and disk device provided with the same

Publication Date: 2012.05.15 KK TOSHIBA

AI summary

According to one embodiment, a slider of a magnetic head is provided with a negative-pressure cavity formed in a facing surface, a leading step portion situated on the upstream side of the negative-pressure cavity, a pair of side portions opposed to each other, a trailing step portion situated on the outlet end side of the negative-pressure cavity, and a pair of embossed portions formed on the facing surface so as to project from the negative-pressure cavity and provided on the outlet side of the negative-pressure cavity with respect to an airflow. The embossed portions individually extend along a second direction so as to be situated individually on the opposite sides of the trailing step portion and are formed so as to be lower than the trailing step portion with respect to the negative-pressure cavity and flush with an outlet-side end surface of the slider.