TAMR Head Alignment Waveguides for Light Source Positioning

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Solution Overview

Problem

Current magnetic recording technologies face challenges in achieving precise alignment of light sources for thermally assisted magnetic recording (TAMR) heads, leading to inefficient power usage and potential interference with the main transmission mode, which affects data storage density and device longevity.

Innovation Solution

The implementation of alignment waveguides on either side of the main waveguide in a TAMR head structure, allowing for partial diversion of light intensity to photo detectors or CCD cameras for measurement, enabling precise alignment without disturbing the main transmission mode and reducing power requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If alignment waveguides are added to the TAMR head structure, then alignment precision is improved, but device complexity increases

Engineering Contradiction:

Improvealignment precisionVSAvoidwaveguide structure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The waveguide structure is segmented into a main waveguide for light transmission and separate alignment waveguides for alignment measurement. This segmentation allows the alignment function to be performed independently without interfering with the main light transmission path, thereby improving alignment precision while keeping the overall system organized and manageable despite the increased complexity.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If light intensity is diverted to photo detectors for alignment measurement, then alignment accuracy is improved, but power consumption increases

Engineering Contradiction:

Improvealignment accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

Only a portion of the light intensity is diverted to the photo detectors for alignment measurement, while the majority of the light continues through the main waveguide for its intended function. This partial diversion achieves sufficient alignment accuracy without requiring excessive power consumption, as the alignment waveguides tap off a fraction of the light rather than diverting the entire beam.

Inventive Principle:

Principle #16Partial or excessive action

3Manufacturing precision

If alignment measurement is performed during TAMR head fabrication, then manufacturing precision is improved, but production time increases

Engineering Contradiction:

Improvealignment precisionVSAvoidfabrication time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The alignment waveguides are incorporated into the TAMR head structure during fabrication, enabling alignment measurements to be performed as part of the manufacturing process rather than as a separate post-processing step. This preliminary integration of alignment functionality allows for precise alignment to be achieved during fabrication without significantly extending the overall production timeline.

Inventive Principle:

Principle #10Preliminary action

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 approach allows for accurate alignment with minimized power consumption, extending the lifespan of the light source and maintaining optimal data storage density without interfering with the main transmission mode during the TAMR write process.

Implementation Method 1

The wave guide serves as an intermediate path to guide light from a light source to the PA or PG

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

the light optical mode couples to the local plasmon mode of the PA or to the propagating plasmon mode of the PG. After the optical energy is transformed to plasmon energy, either with local plasmon excitation in the PA or with energy transmission along the PG, it is concentrated at the medium location where heating is desired

Methodology Applied

Scientific EffectSurface plasmon mode coupling:

Implementation Method 3

Plasmon mode 7 further delivers the optical power toward the ABS and locally heats a medium (not shown) placed underneath the plasmon generator 2

Methodology Applied

Scientific EffectPlasmon heating:

Implementation Method 4

allowing for partial diversion of light intensity to photo detectors or CCD cameras for measurement

Methodology Applied

Scientific EffectOptical coupling:

Data Source

PatentUS8248898B2Thermally-assisted magnetic recording head having main waveguide and sub-waveguides

Publication Date: 2012.08.21 HEADWAY TECHNOLOGIES INC

AI summary

A waveguide structure for aligning a light source to a center waveguide (CWG) in a TAMR head is disclosed and includes two alignment waveguides (AWVG) symmetrically formed about a plane that bisects the CWG lengthwise dimension. Each AWVG has a light coupling section formed parallel to a side of the CWG and captures 0.5% to 10% of the light in the CWG. Each AWVG has an outlet that directs light to a photo detector or camera so that light intensity measurements lAWVG1 and lAWVG2 for first and second AWVG, respectively, can be taken at various positions of the light source. Optimum alignment occurs when (lAWVG1+lAWVG2) reaches a maximum value and |lAWVG1−lAWVG2| has a minimum value. AWVG outlets may be at the ABS, or at the side or back end of a slider. Measurement sensitivity is increased by decreasing the width of the AWVG.