Magnetic Recording Head Transducer Offset and Protrusion Control
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Solution Overview
Problem
Existing magnetic recording heads face challenges in independently controlling the distance between read and write transducers, leading to unintended protrusion and potential contact with the magnetic recording medium, which can result in head crashes or reduced recording density.
Innovation Solution
A magnetic recording head design with a side-by-side configuration of read and write transducers, incorporating a spacer layer with specific thermal conductivity, elasticity, and coefficient of thermal expansion to minimize unintended protrusion, and using thermos-resistive or piezoelectric protrusion controllers for independent actuation of each transducer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a magnetic recording head uses a conventional design with read and write transducers in close proximity, then the device complexity is reduced and manufacturing is easier, but independent control of transducer spacing is lost leading to unintended protrusion and potential head crashes
Solution Approach 1:
The magnetic recording head is segmented into distinct read and write transducer components with independent protrusion control. Each transducer has its own protrusion controller (heater or piezoelectric device) that can independently adjust its position relative to the recording medium, allowing the read and write transducers to be controlled separately to prevent unintended protrusion and head crashes.
Solution Approach 2:
A spacer layer is introduced as an intermediary element between the read and write transducers. This spacer provides mechanical separation and thermal isolation, preventing heat from one transducer from affecting the other's protrusion control. The spacer ensures that protrusion of one transducer does not cause unintended protrusion of the other, maintaining reliable spacing control.
2Manufacturing precision
If the reader and writer are positioned close together to increase areal density, then recording density improves, but thermal interference between transducers causes unintended protrusion and spacing control issues
Solution Approach 1:
A thermally insulating spacer layer is positioned between the read and write transducers to block thermal interference. This intermediary material prevents heat from one transducer from transferring to the other, ensuring that temperature changes in one transducer do not cause unintended thermal expansion or protrusion in the adjacent transducer, thereby maintaining precise spacing control.
Solution Approach 2:
The spacer layer is strategically positioned only in the regions where thermal isolation is needed between adjacent transducers. This localized application of thermal insulation allows the transducers to be positioned close together for high areal density while preventing thermal crosstalk in the critical interfaces between them, maintaining both precision and density.
3Manufacturing precision
If protrusion control is implemented for one transducer, then spacing control for that transducer improves, but thermal expansion or mechanical coupling causes unintended protrusion of the other transducer
Solution Approach 1:
The protrusion control system is segmented into independent control units for each transducer. Each transducer has its own protrusion controller (heater or piezoelectric device) that can be actuated independently without affecting the other transducer's position. This segmentation allows precise spacing control for each transducer while maintaining ease of independent operation.
Solution Approach 2:
A mechanically decoupling spacer layer acts as an intermediary that prevents mechanical coupling between transducers. When one transducer is actuated for protrusion control, the spacer prevents this mechanical movement from being transmitted to the other transducer, ensuring independent actuation while maintaining precise spacing control for each transducer separately.
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 allows for precise and independent control of transducer spacing, reducing the risk of contact and enhancing areal density and media servo format efficiency, while maintaining stable fly height and preventing head crashes.
Implementation Method 1
a first portion of the spacer layer between the reader and the writer effective to minimize an amount of unintended protrusion of the reader or the writer
Implementation Method 2
a heater actuator heats a specific portion of a magnetic head at a location of the reader or the writer to cause a controlled amount of thermal expansion of the portion of the magnetic head
Implementation Method 3
by a piezoelectric device, a heater (an 'electrothermal' heater), or another type of protrusion controller
Data Source
AI summary
Described are magnetic recording heads that include a read transducer and a write transducer, with the two transducers being arranged in a side-by-side configuration.