Balanced Shield Design for Read Head Sensors
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Solution Overview
Problem
Existing magnetic read heads face challenges in achieving balanced saturation fields due to non-identical shields, leading to unbalanced out-of-plane magnetic fields, which affects the reading of high recording densities in data storage devices.
Innovation Solution
The magnetic read head design includes shields with different materials, layer configurations, and fabrication processes, ensuring that the ratio of thickness to height for each shield is substantially identical to achieve balanced saturation fields, thereby canceling out-of-plane magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If shields are made with different materials, layer configurations, or dimensions to meet manufacturing requirements, then ease of manufacture is improved, but magnetic field balance deteriorates due to unbalanced saturation fields
Solution Approach 1:
The patent applies parameter changes by adjusting the thickness-to-height ratio parameter of shields to achieve balanced saturation fields. By controlling this geometric parameter, the patent enables shields with different materials and layer configurations to produce equivalent magnetic saturation fields, resolving the contradiction between manufacturing flexibility and magnetic field balance.
Solution Approach 2:
The patent utilizes composite materials by allowing shields to be constructed from different material compositions and layer structures. This enables each shield to be optimized for its specific manufacturing requirements while the overall thickness-to-height ratio ensures balanced magnetic saturation fields, combining material diversity with magnetic field uniformity.
2Productivity
If recording density is increased by narrowing write track width and pitch, then productivity is improved, but measurement precision deteriorates due to unbalanced magnetic fields affecting sensor performance
Solution Approach 1:
The patent applies parameter changes by optimizing the thickness-to-height ratio of shields to achieve balanced saturation fields. This parameter control eliminates unbalanced out-of-plane magnetic fields that would otherwise interfere with sensor performance, enabling accurate reading at high recording densities of 2 Tbit/in2 and above.
3Ease of manufacture
If shield dimensions are made non-identical to accommodate different fabrication processes, then ease of manufacture is improved, but device complexity increases due to need for precise ratio control
Solution Approach 1:
The patent applies parameter changes by establishing a specific thickness-to-height ratio for shields. This parameter specification simplifies the manufacturing process by providing clear dimensional guidelines that work across different fabrication processes and material types, reducing device complexity despite allowing manufacturing flexibility.
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 design enhances the linearity and performance of the read head by minimizing unbalanced magnetic fields, improving sensor transfer curves and reducing disturbances, resulting in better data reading capabilities for high recording densities.
Implementation Method 1
The ratio of the thickness to the height for the shields are substantially identical to ensure that the saturation field of individual shields are substantially identical and balanced
Data Source
AI summary
The present disclosure generally relates to a read head of a data storage device. The read head includes a read sensor sandwiched between two shields. The shields can have different materials as well as a different number of layers. Furthermore the shields can be fabricated by different processes and have different heights and thicknesses. The ratio of the thickness to the height for the shields are substantially identical to ensure that the saturation field are substantially identical and balanced.