Heat Assisted Magnetic Recording Head with Optical Waveguide
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Solution Overview
Problem
Current heat-assisted magnetic recording technologies face challenges in compactly mounting heat sources and optical paths on small magnetic heads, insufficient laser power for high-temperature heating, and issues with edge noise and crosstalk in magnetic recording.
Innovation Solution
A heat-assisted magnetic recording head with a laser diode and optical waveguides that direct a heating laser beam to a magnetic recording medium, using a mode-conversion type waveguide and a compact design to separate magnetic and optical systems, reducing edge noise and crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a light beam is used to heat the recording film in heat assisted recording, then the coercivity is lowered enabling recording, but the magnetic system and optical system must be separated which increases device complexity
Solution Approach 1:
The patent combines the magnetic recording element and optical heating element into a single integrated magnetic head structure. The optical waveguide is positioned adjacent to the recording element within the same head assembly, allowing simultaneous magnetic field application and localized heating without requiring separate magnetic and optical systems.
Solution Approach 2:
The patent introduces an optical waveguide as an intermediary component that delivers the laser beam precisely to the recording region. This waveguide acts as a mediator between the external laser source and the recording film, enabling controlled heating while maintaining the integrated head structure.
2Reliability
If various members for heat assistance are mounted on a small magnetic head, then heat assisted recording is achieved, but compact mounting becomes difficult
Solution Approach 1:
The patent nests the optical waveguide within the same plane and structure as the magnetic recording element. The waveguide is positioned in the trailing edge region of the magnetic head, utilizing the same floating slider structure, thereby achieving compact integration without increasing overall head size.
Solution Approach 2:
The patent arranges the optical waveguide and magnetic recording element in a two-dimensional layout on the floating slider surface, with the waveguide positioned adjacent to and slightly behind the recording element. This spatial arrangement in multiple dimensions allows both components to coexist in a compact configuration.
3Productivity
If the crystal grain diameter is made smaller to increase recording density, then higher density is achieved, but thermal disturbance causes magnetization instability
Solution Approach 1:
The patent applies heating to the recording film before and during the application of the magnetic field. By pre-heating the recording region to a temperature near the Curie point before magnetic field application, the coercivity is reduced in advance, enabling stable magnetization of small grain structures without thermal disturbance.
Solution Approach 2:
The patent dynamically changes the temperature parameter of the recording film during the recording process. By controlling the laser power and exposure time, the film temperature is raised to reduce coercivity for easy magnetization, then allowed to cool to stabilize the recorded magnetization in small crystal grains.
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
Enables high-density magnetic recording with reduced edge noise and crosstalk, achieving efficient heating of the recording film while maintaining a compact and effective magnetic recording system.
Implementation Method 1
a laser diode serving as a light source of a heating laser beam; and an irradiating optical waveguide, arranged close to the magnetic recording element, for directing the heating laser beam from the irradiating optical waveguide at the front side thereof to a minute magnetizing region of a magnetic recoding medium
Data Source
AI summary
A heat assisted magnetic recording head is provided, which can prevent an effect of a heat in a laser diode when a magnetic recording region is heated by a heating laser beam and which can reduce its size and weight. In the heat assisted magnetic recording head, a recording magnetic pole, a magnetic recording element, a magnetic read element, an optical waveguide, and an irradiating optical waveguide are attached to a floating slider provided below a suspension. The laser diode is arranged on an opposite side of the suspension to the floating slider. The heating laser beam emitted from the laser diode is directed to the irradiating optical waveguide through the optical waveguide, so that a magnetic recording medium is irradiated with the heating laser beam exiting from the irradiating optical waveguide.