Magnetic Head Bias Voltage for Contamination Control

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Solution Overview

Problem

Magnetic storage apparatuses face contamination issues due to micro contaminants from carbon and carbon nitride products generated by the carbon protective layer, which adhere to the magnetic head due to potential differences between the recording medium and the head, leading to deteriorated write and read characteristics and stability.

Innovation Solution

A magnetic storage apparatus with a laminated structure including a magnetic layer and a carbon protective layer, where a bias circuit supplies a voltage range of −0.2 V to −1.0 V to the magnetic head element to reduce the adhesion of contaminants, optimizing the potential difference to prevent contamination while minimizing the risk of discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the floating amount of the magnetic head is reduced to improve recording density, then recording density is improved, but contaminants on the magnetic recording medium can adhere to the magnetic head causing deterioration of write and read characteristics

Engineering Contradiction:

Improverecording densityVSAvoidwrite and read characteristics

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent changes the electrical potential parameter of the magnetic head to a specific range (−0.2 V to −1.0 V) to reduce contaminant adhesion. This parameter change allows the magnetic head to maintain extremely small floating amounts for high recording density while preventing contamination that would otherwise deteriorate write and read characteristics.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If a small floating amount is used to achieve high recording density, then recording density is improved, but the magnetic head becomes vulnerable to contamination from the magnetic recording medium

Engineering Contradiction:

Improverecording densityVSAvoidcontaminant adhesion

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the potentially harmful effect of close proximity to the magnetic recording medium into a beneficial effect by applying a negative potential to the magnetic head. This negative potential repels negatively charged contaminants (carbon and carbon nitride products), transforming the close proximity from a contamination risk into an opportunity for improved recording density without the harmful effects.

Inventive Principle:

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

3Reliability

If the magnetic head is electrically connected to the magnetic recording medium to prevent discharge, then discharge prevention is achieved, but contaminants can still transfer to the magnetic head

Engineering Contradiction:

Improvedischarge preventionVSAvoidcontaminant transfer

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the electrical potential parameter from 0 V (electrical connection) to a negative range (−0.2 V to −1.0 V). This parameter change maintains discharge prevention while simultaneously creating an electrical repulsion force that prevents contaminant transfer, solving both issues with a single optimized parameter setting.

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

The solution effectively reduces the adhesion of contaminants to the magnetic head, maintaining stable recording and reproducing characteristics and preventing damage, even at high recording densities, by controlling the potential difference between the magnetic head and the recording medium.

Implementation Method 1

the bias circuit supplies to the first magnetic head element a voltage which is in a range of −0.2 V to −1.0 V with respect to a potential of the magnetic recording medium... effectively reduces the adhesion of contaminants to the magnetic head... by controlling the potential difference between the magnetic head and the recording medium

Methodology Applied

Scientific EffectElectrostatic repulsion: Electrostatics

Data Source

PatentUS11587580B2Magnetic storage apparatus

Publication Date: 2023.02.21 RESONAC HARD DISK CORP

AI summary

A magnetic storage apparatus includes a disk-shaped magnetic recording medium, a motor which drives and rotates the magnetic recording medium, a magnetic head, including a first magnetic head element which reads information from the magnetic recording medium, and a second magnetic head element which writes information to the magnetic recording medium, and a bias circuit which supplies a predetermined bias voltage to the first magnetic head element. The magnetic recording medium has a laminated structure including a magnetic layer disposed above a substrate, and a carbon protective layer disposed above the magnetic layer. The bias circuit supplies to the first magnetic head element a voltage which is in a range of −0.2 V to −1.0 V with respect to a potential of the magnetic recording medium.