Magnetic Head Sensor Positioning for Contact Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In magnetic heads for perpendicular magnetic recording, the presence of a yoke layer connected to the write shield and main pole complicates the control of distance and detection of contact with the recording medium, hindering the protrusion of the medium facing surface and effective contact detection.
Innovation Solution
A magnetic head design featuring a write shield, a gap part, and a sensor, with the sensor positioned between the yoke layer and a coupling part that allows for controlled expansion and contact detection, enabling the medium facing surface to protrude without hindrance from the yoke layer's position relative to the main pole.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a write shield and return path section are added to prevent adjacent track erase, then recording density is improved, but device complexity increases
Solution Approach 1:
The return path section is integrated within the write shield structure, with the yoke layer positioned behind the main pole and the write shield wrapping around the main pole end face. This nested arrangement allows the return path to be contained within the shield structure, preventing adjacent track erase while minimizing additional complexity
Solution Approach 2:
The return path section is positioned in the depth dimension (behind the main pole) rather than extending laterally. The yoke layer is located at a position behind the main pole along the direction of travel, utilizing the third dimension to achieve flux return without increasing lateral footprint or track interference
2Manufacturing precision
If the medium facing surface is made to protrude to control distance, then distance control is improved, but contact detection becomes more difficult
Solution Approach 1:
A sensor is introduced as an intermediary element positioned between the yoke layer and the coupling part. This sensor detects contact between the medium facing surface and the recording medium by monitoring changes in the electrical field or capacitance, enabling contact detection without direct mechanical contact that would interfere with the protrusion mechanism
Solution Approach 2:
The contact detection mechanism replaces direct mechanical contact sensing with an electrical field-based sensor. The sensor detects contact through changes in electrical properties (capacitance or resistance) rather than mechanical pressure, allowing the medium facing surface to protrude freely while still enabling accurate contact detection
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 design allows for precise control of the distance between the medium facing surface and the recording medium, facilitating effective contact detection and preventing adjacent track erase, thereby enhancing recording density and write characteristics.
Implementation Method 1
a coil that produces a magnetic field corresponding to data to be written on the recording medium; and a main pole that allows a magnetic flux corresponding to the magnetic field produced by the coil to pass, and produces a write magnetic field
Implementation Method 2
at least one heater that generates heat for making part of the medium facing surface protrude
Implementation Method 3
The sensor is a resistor that varies in resistance with a change in its own temperature which occurs when part of the medium facing surface makes contact with the recording medium
Data Source
AI summary
A magnetic head includes a main pole, a write shield, a return path section, a heater that generates heat for making part of a medium facing surface protrude, and a sensor that detects contact of the part of the medium facing surface with a recording medium. The return path section includes: a yoke layer located backward of the main pole along the direction of travel of the recording medium; a first coupling part coupling the yoke layer and the write shield to each other; and a second coupling part located away from the medium facing surface and coupling the yoke layer and the main pole to each other. The first coupling part has an end face facing toward the yoke layer. This end face includes a middle portion spaced from the yoke layer and facing the yoke layer, and two side portions located on opposite sides of the middle portion in a track width direction and in contact with the yoke layer. The sensor is located between the middle portion and the yoke layer.