Thermally-Assisted Magnetic Recording Head Plasmon Generator Shield Overlap
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Solution Overview
Problem
Existing thermally-assisted magnetic recording heads face challenges in increasing linear recording density due to the difficulty in achieving a high write field intensity gradient, particularly when using a plasmon generator, as the distance between the main pole and the bottom shield is too large, hindering the effective operation of the bottom shield and limiting the recording density.
Innovation Solution
A thermally-assisted magnetic recording head design that includes a main pole, a plasmon generator, a waveguide, and a shield, where the shield overlaps only the first region of the front end face of the core, allowing the main pole and shield to be in close proximity, and the near-field light generating part is positioned between the first and second end faces, enabling a large write field intensity gradient and improved recording density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the distance between the main pole and the bottom shield is increased to accommodate the plasmon generator, then the plasmon generator can be properly positioned, but the write field intensity gradient is reduced and linear recording density cannot be increased
Solution Approach 1:
The patent repositions the shield from a configuration where it is distant from the main pole to one where it overlaps the first region of the front end face of the core, utilizing the vertical dimension and spatial arrangement to reduce the horizontal distance between main pole and shield while maintaining functional effectiveness
Solution Approach 2:
The shield is designed to overlap only the first region of the front end face of the core, creating a localized magnetic flux management zone that allows close proximity to the main pole while maintaining effective shielding in the critical writing region
2Productivity
If the main pole and shield are placed in close proximity to increase write field intensity gradient, then linear recording density is improved, but the plasmon generator positioning and near-field light generation are compromised
Solution Approach 1:
The front end face of the core is divided into two regions: a first region that overlaps with the shield and a second region that does not. This segmentation allows the shield to be positioned close to the main pole for high write field intensity gradient while the plasmon generator can be positioned to utilize the second region for effective near-field light generation
Solution Approach 2:
The waveguide core acts as an intermediary structure that separates the magnetic flux path (main pole-shield region) from the optical path (plasmon generator region), allowing both systems to operate in close proximity without interfering with each other's functionality
3Ease of manufacture
If the bottom shield is positioned far from the main pole, then component assembly is simplified, but the bottom shield cannot effectively operate to prevent erroneous writing
Solution Approach 1:
The shield is designed with localized functionality, overlapping only the first region of the front end face of the core, which concentrates the magnetic flux management effect where it is most needed for preventing erroneous writing, while simplifying the overall assembly by not requiring extensive shielding structures
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 allows for a significant increase in linear recording density by enhancing the write field intensity gradient and preventing erroneous writing, while maintaining effective magnetic flux management and near-field light distribution.
Implementation Method 1
a plasmon generator, which is a piece of metal that generates near-field light from plasmons excited by irradiation with laser light
Implementation Method 2
use near-field light to lower the coercivity of the recording medium for data writing
Implementation Method 3
The laser light to be used for generating near-field light is typically guided through a waveguide, which is provided in the slider, to the plasmon generator disposed near the medium facing surface of the slider
Implementation Method 4
a write head section including an induction-type electromagnetic transducer for writing
Implementation Method 5
a recording medium having high coercivity. When writing data, a write magnetic field and heat are simultaneously applied to the area of the recording medium where to write data, so that the area rises in temperature and drops in coercivity
Data Source
AI summary
A plasmon generator has a near-field light generating part located between an end face of a main pole located in a medium facing surface and an end face of a shield located in the medium facing surface. A waveguide has a core having a front end face facing toward the medium facing surface. The front end face has first and second end portions located at opposite ends in the direction of travel of a recording medium. The first end portion is located closer to the near-field light generating part than is the second end portion. Either a main pole or a shield overlaps only a region of the front end face of the core when viewed in a direction perpendicular to the medium facing surface, the region extending from a midpoint position between the first and second end portions to the first end portion.