Heat-Assisted Magnetic Recording Head Waveguide Design
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Solution Overview
Problem
Heat-assisted magnetic recording heads face challenges in reducing light transmission loss and noise generation due to the complexity of collimating means and large light beam sizes, which affect the recording density and stability of magnetic information.
Innovation Solution
A heat-assisted magnetic recording head with a waveguide featuring a tapered portion and an S-shaped bent portion, along with a light reflective surface, to reduce light loss and noise, and an optical transmission medium using a GRIN fiber with a self-focusing function, eliminating the need for separate collimating means and focusing lenses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a grating coupler is used to couple light into the waveguide, then light can be transmitted to the magnetic recording medium, but light loss is large and noise is generated due to diffused reflection
Solution Approach 1:
The patent removes the grating coupler from the optical system. Instead of using a grating coupler to couple light into the waveguide, the invention uses direct end-fire coupling where light is incident directly onto the waveguide input face, eliminating the source of diffused reflection and associated noise while reducing light loss.
Solution Approach 2:
The patent inverts the conventional approach by placing the light source and waveguide in a configuration where light couples directly into the waveguide without requiring a grating structure. The waveguide is positioned such that its input face is accessible to light from the light source, reversing the typical grating-based coupling methodology.
2Ease of operation
If complicated collimating means are used to direct light beams, then light can be directed toward the grating coupler, but device complexity increases and light beam loss occurs due to slider shaking
Solution Approach 1:
The patent removes the complicated collimating means from the system. By using direct end-fire coupling into the waveguide, the invention eliminates the need for complex collimating optics, reducing device complexity and removing the source of light beam loss associated with slider shaking.
Solution Approach 2:
The waveguide itself acts as an intermediary that directly receives light from the light source without requiring intermediate collimating optics. The waveguide's input face serves as the interface between the light source and the optical path, simplifying the overall system architecture.
3Quantity of substance
If light beams are made large in size, then they can be easily generated, but light loss increases and noise is generated due to diffused reflection from the grating coupler
Solution Approach 1:
The patent removes the grating coupler that caused diffused reflection of large light beams. By using direct end-fire coupling, the invention allows large light beams to be efficiently coupled into the waveguide without the loss and noise problems associated with grating-based coupling of large beams.
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
The solution enhances optical coupling efficiency, reduces light loss, and simplifies the recording head structure, allowing for improved recording density and stability while minimizing the risk of collision with the magnetic recording medium.
Implementation Method 1
a waveguide which transmits light therethrough disposed to be adjacent to the recording portion and which emits the light toward the magnetic recording medium
Implementation Method 2
an optical transmission medium using a GRIN fiber with a self-focusing function, eliminating the need for separate collimating means and focusing lenses
Implementation Method 3
a light reflective surface, to reduce light loss and noise
Implementation Method 4
a heat-assisted magnetic recording head for heating a magnetic recording medium locally by irradiating a light beam
Data Source
AI summary
A heat-assisted magnetic recording head and a recording apparatus including the same are provided. The heat-assisted magnetic recording head includes a recording portion which produces magnetic field for recording information to a magnetic recording medium, and a waveguide which transmits light therethrough disposed to be adjacent to the recording portion and which emits the light toward the magnetic recording medium, wherein the waveguide comprises a light incident surface; a tapered portion having progressively narrower sections along the transmission direction of the light incident on the light incident surface and entering the waveguide; and a light-emitting surface which emits the light after the light is transmitted through the tapered portion.