Magnetic Head with Multiple Reproducing Elements and Magnetic Shields
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Solution Overview
Problem
In hard disk drives (HDDs), the inter-track interference (ITI) of reproduction signals varies significantly with slight changes in skew angle due to the required traveling-directional distance between reproducing elements, affecting decoding accuracy and track density.
Innovation Solution
A magnetic recording/reproducing apparatus with a reproducing head having a plurality of reproducing elements, where the distance between elements is minimized by using insulating films and magnetic shields to maintain consistent inter-element distance, reducing inter-track interference and enhancing decoding accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sufficient traveling-directional distance Gd is provided between reproducing elements, then signal detection paths are properly isolated, but inter-track interference varies significantly with skew angle changes
Solution Approach 1:
The patent transitions from isolating signal paths in the traveling direction (one dimension) to isolating them in the track width direction (another dimension) using magnetic shields. This allows the reproducing elements to be positioned close together in the traveling direction while maintaining isolation through magnetic shields extending in the track width direction, thereby resolving the contradiction between compact element spacing and reliable signal isolation.
Solution Approach 2:
Magnetic shields are introduced as intermediary structures between reproducing elements. These shields act as mediators that provide magnetic isolation and define signal detection paths without requiring large physical distances between elements. The shields extend from the air bearing surface toward the opposite side, creating magnetic barriers that isolate adjacent element paths while allowing compact element spacing.
2Reliability
If the traveling-directional distance Gd is increased, then signal isolation is improved, but the change in inter-element distance Rp increases with skew angle
Solution Approach 1:
The invention changes the isolation mechanism from relying on traveling-directional distance to using magnetic shields extending in the track width direction. This dimensional shift allows isolation performance to be maintained independently of the skew angle, as the shields perpendicular to the track provide consistent magnetic barriers regardless of the head's angular orientation during operation.
Solution Approach 2:
The magnetic shields are positioned locally between adjacent reproducing elements, creating localized magnetic isolation zones. This local isolation approach ensures that each element's signal detection path is independently protected by its own magnetic shields, making the system's performance less sensitive to global changes in skew angle while maintaining adaptability to radial position variations.
3Manufacturing precision
If reproducing elements are positioned closer together, then track density is enhanced, but signal detection path isolation becomes difficult
Solution Approach 1:
Magnetic shields serve as intermediary structures that enable close positioning of reproducing elements while maintaining signal path isolation. The shields extend from the air bearing surface toward the opposite side of the substrate, creating magnetic barriers that effectively isolate adjacent element paths even when elements are positioned very close together, thus enabling high track density without sacrificing isolation reliability.
Solution Approach 2:
Instead of relying on large separations in the traveling direction to achieve isolation, the patent uses magnetic shields extending in the track width direction to provide isolation. This allows reproducing elements to be positioned close together in the traveling direction (enhancing track density) while the shields provide the necessary magnetic isolation in the perpendicular dimension.
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 maintains consistent inter-track interference across different radial positions, improving decoding accuracy and track density by reducing the delay in signal processing and simplifying real-time signal processing circuits.
Implementation Method 1
a first reproducing element 311, a second reproducing element 312 and a third reproducing element 313
Data Source
AI summary
A magnetic head includes a plurality of reproducing elements so that the magnetic head can acquire reproduction signals from a plurality of tracks at the same time. The magnetic head includes a first reproducing element, a first magnetic film formed on a first side wall of the first reproducing element with a first side wall insulating film interposed therebetween, a second magnetic film formed on a second side wall of the first reproducing element with a second side wall insulating film interposed therebetween, a second reproducing element electrically isolated from the first reproducing element and formed on the first magnetic film, a third magnetic film formed on the first magnetic film, and a fourth magnetic film formed on the first reproducing element and electrically isolated from the second reproducing element.