Heat-Assisted Magnetic Recording Head Convergent Lens Alignment
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Solution Overview
Problem
Heat-assisted magnetic recording faces challenges in aligning incident light with a waveguide due to increased distance from the light source, leading to energy loss and reduced efficiency in generating near-field light.
Innovation Solution
A heat-assisted magnetic recording head design that includes a convergent lens to focus light from a laser diode onto a waveguide, reducing the light's diameter and improving alignment, which is supported by a dielectric material layer with a groove accommodating the lens, allowing for efficient light transmission and alignment with the waveguide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the light source is placed away from the slider, then the alignment complexity is reduced, but the energy loss of light increases due to extended optical path
Solution Approach 1:
The patent introduces a mirror as an intermediary component to redirect light from a remotely positioned laser source to the waveguide. This allows the light source to be placed away from the slider (reducing alignment complexity) while maintaining efficient light delivery through the reflective path, thereby preventing energy loss that would occur with extended optical paths without intermediaries.
2Loss of energy
If the light source is fixed to the slider, then the optical path length is reduced, but the alignment precision requirement increases
Solution Approach 1:
The mirror serves as a flexible intermediary that can be positioned to optimize the optical path. By using the mirror to redirect light, the system achieves short effective optical path length (reducing energy loss) while allowing more flexible positioning of the laser source, thereby reducing the stringent alignment precision requirements that would exist in a direct coupling configuration.
3Manufacturing precision
If the laser light diameter is reduced for better waveguide alignment, then the alignment precision is improved, but the light energy concentration decreases
Solution Approach 1:
The patent employs a cylindrical lens to selectively focus light in one dimension (the dimension perpendicular to the waveguide face) while maintaining beam width in the other dimension. This dimensional differentiation allows precise alignment with the waveguide in the critical dimension without unnecessarily reducing the overall light energy, as the beam remains wide in the non-critical dimension where alignment tolerance is higher.
Solution Approach 2:
The cylindrical lens creates non-uniform light distribution with different characteristics in different spatial dimensions. The light is focused to a smaller diameter only in the dimension where waveguide alignment is critical, while maintaining larger beam width in the dimension where alignment is less sensitive. This local differentiation of light quality optimizes both alignment precision and energy utilization.
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 convergent lens ensures that the light is focused to a smaller diameter, preventing energy loss and facilitating precise alignment, thereby enhancing the efficiency of near-field light generation and data recording.
Implementation Method 1
A heat-assisted magnetic recording head design that includes a convergent lens to focus light from a laser diode onto a waveguide, reducing the light's diameter and improving alignment
Implementation Method 2
The laser light applied to the plasmon antenna excites surface plasmons on the plasmon antenna. The surface plasmons propagate to the near-field light generating part of the plasmon antenna, and the near-field light generating part generates near-field light based on the surface plasmons
Implementation Method 3
When recording data, a magnetic field and heat are simultaneously applied to the area of the recording medium where to record data, so that the area rises in temperature and drops in coercivity for data recording
Implementation Method 4
In heat-assisted magnetic recording, near-field light is typically used as a means for applying heat to the recording medium
Data Source
AI summary
A heat-assisted magnetic recording head includes a magnetic pole, a waveguide that allows light to propagate therethrough, a near-field light generating element that generates near-field light based on the light propagating through the waveguide, a convergent lens, and a laser diode disposed above the waveguide. The convergent lens transmits light that is emitted from the laser diode, so that the light transmitted through the convergent lens is incident on the waveguide.