Multi-read Sensor Narrow Read Gap Structure

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Solution Overview

Problem

Multi-element magnetic heads face challenges in narrowing the read gap width while maintaining sensitivity and reducing noise, which are essential for achieving higher recording density in magnetic data storage systems.

Innovation Solution

The design includes a lower shield layer, multiple magnetoresistive (MR) elements, back wiring layers positioned away from the media-facing surface, and an upper shield layer configured to communicate with the MR elements, allowing for separate signal extraction and narrowing of the read gap width without significant noise increase.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the read gap width is narrowed to increase recording density, then the recording density is improved, but the sensitivity is lowered and noise is increased

Engineering Contradiction:

Improverecording densityVSAvoidsensitivity

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent divides the sensor into multiple independent magnetoresistive elements (first MR element, second MR element, etc.) arranged in parallel. Each element has its own read gap, allowing individual optimization of gap width for high density while maintaining larger element dimensions for sufficient sensitivity and signal strength.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent combines multiple MR elements into a single multi-element sensor assembly that reads from the same track simultaneously. The outputs of individual elements are processed together to achieve high-density reading capability while maintaining robust sensitivity through signal combination.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If the element size is increased to reduce noise and improve sensitivity, then the sensitivity is improved, but the read gap width is expanded

Engineering Contradiction:

ImprovesensitivityVSAvoidread gap width

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent transitions from a single planar dimension to multiple dimensions by stacking MR elements in parallel arrangements. Elements can be positioned at different heights or lateral positions while all reading from the same track, enabling size optimization without gap expansion.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent nests multiple MR elements within a compact sensor structure where elements are arranged to overlap or interdigitate. This nesting allows larger effective element areas for sensitivity while maintaining a compact overall footprint and narrow read gap.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Adaptability or versatility

If multiple wiring layers are added to extract signals from multiple elements, then the signal extraction capability is improved, but the device complexity is increased

Engineering Contradiction:

Improvesignal extraction capabilityVSAvoidwiring layer structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent designs wiring layers that serve multiple functions: they provide electrical connections to multiple MR elements, act as magnetic shields, and in some cases serve as structural support. This multi-functionality reduces the need for separate dedicated wiring for each element.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent introduces insulating layers as intermediaries between wiring layers and MR elements, and between adjacent wiring layers. These intermediaries enable complex wiring arrangements while preventing unwanted electrical interactions and magnetic interference.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 enables the magnetic head to read data from a magnetic medium with increased recording density while maintaining sensitivity and reducing noise, facilitating the extraction of signals from multiple elements along the element height direction.

Implementation Method 1

Magnetoresistive effect type magnetic heads are employed as sensors for reading magnetic information (data) recorded on a magnetic recording medium

Methodology Applied

Scientific EffectMagnetoresistive effect: Magnetoresistance

Data Source

PatentUS8953284B1Multi-read sensor having a narrow read gap structure

Publication Date: 2015.02.10 WESTERN DIGITAL TECHNOLOGIES INC

AI summary

In one embodiment, a magnetic head includes a lower shield layer positioned at a media-facing surface of the magnetic head, at least two magnetoresistive (MR) elements positioned above the lower shield layer, each MR element extending in an element height direction away from the media-facing surface of the magnetic head, back wiring layers positioned above at least one lower layer of each of the MR elements at a position away from the media-facing surface of the magnetic head in the element height direction, wherein the back wiring layers are configured to electrically communicate with the MR elements and configured to separately extract signals from each MR element during a read operation, and an upper shield layer positioned above the MR elements that is configured to electrically communicate with the MR elements.