Heat-Assisted Magnetic Recording Head Alignment Using Optical Markers
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Solution Overview
Problem
The challenge in manufacturing heat-assisted magnetic recording heads is achieving high alignment accuracy between the light source unit and the slider, which is crucial for efficient heat-assisted magnetic recording, as existing methods face difficulties in accurately locating the light-emission center and incident center during alignment, leading to reduced manufacturing yield and increased costs.
Innovation Solution
A manufacturing method that involves using markers and displacement measuring means, such as laser displacement meters, to align the light source unit with the slider, ensuring precise positioning of the light-emission center and incident center, thereby improving alignment accuracy and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional alignment methods are used to join the light source unit to the slider, then the manufacturing process is simple, but the alignment accuracy between the light-emission center and incident center is insufficient
Solution Approach 1:
The patent introduces markers as intermediary reference objects on both the light source unit and slider. These markers serve as mediators for alignment, allowing the light-emission center and incident center to be aligned indirectly through marker coincidence rather than direct observation, thereby achieving high alignment accuracy without complex alignment procedures
Solution Approach 2:
The patent creates a simplified reference model by using markers that represent the critical alignment points. Instead of directly aligning the complex light-emission center and incident center, the system uses marker positions as copies or proxies for these critical points, making the alignment process straightforward while maintaining high precision
2Productivity
If the light source unit is integrated within the slider, then the structure is compact, but the manufacturing yield decreases due to multiplication of process yields
Solution Approach 1:
The patent divides the heat-assisted magnetic recording head into separate functional modules: the slider and the light source unit. This segmentation allows each component to be manufactured and evaluated independently, avoiding the multiplication of process yields that would occur with full integration, while still achieving a compact final structure through joining
Solution Approach 2:
The patent positions the light source unit on the back surface of the slider, utilizing the third dimension (depth/thickness direction) rather than planar integration. This dimensional separation allows independent evaluation and manufacturing of the light source unit while maintaining a compact overall structure, as the light source is located far from the opposed-to-medium surface
3Reliability
If the light source is positioned close to the opposed-to-medium surface, then the alignment distance is short, but the light source suffers mechanical shock directly during operation
Solution Approach 1:
The patent positions the light source unit on the back surface of the slider, creating a physical buffer zone between the light source and the opposed-to-medium surface. This spatial separation acts as a cushion against mechanical shocks during operation, protecting the light source while maintaining reasonable alignment distance through the marker-based alignment system
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 method enables reliable high-accuracy alignment of the light source unit and slider, enhancing the manufacturing yield of heat-assisted magnetic recording heads and reducing production costs by avoiding the need for complex optical components and precise alignment techniques.
Implementation Method 1
a light source which is provided on a source-installation surface of the unit substrate and whose surface including a light-emission center is positioned on the joining surface side
Implementation Method 2
heat-assisted magnetic recording technique is proposed, in which a magnetic head writes data to the magnetic recording medium formed of a material originally having large magnetic anisotropy energy KU, by reducing the anisotropic magnetic field of the medium with heat supplied to the medium just before the write field is applied
Implementation Method 3
a waveguide for guiding an incident light to the opposed-to-medium surface side, an end of the waveguide on the opposite side to the opposed-to-medium surface reaching an end surface of the head part on the opposite side to the opposed-to-medium surface
Data Source
AI summary
Provided is a method for manufacturing a heat-assisted magnetic recording head, capable of joining a light source unit and a slider with a sufficiently high alignment accuracy. In the method, the unit including a light source is joined to the slider including a head part. First, at least one marker provided on the head-part end surface is set so that the distance from the waveguide incident center to the marker end is substantially equal to the distance from the light-emission center of the light source to the end surface of the light source. After that, the unit and slider are relatively moved while keeping the unit in surface contact with the slider, and the relative positions are set so that the end of the marker coincides with, or is at a distance within an acceptable range from, the edge of the surface of the light source.