Heating Element Lower-Resistance Portion for Thermal Stability
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Solution Overview
Problem
In magnetic disk drive apparatuses, the miniaturization of thin-film magnetic heads leads to challenges in stabilizing the flying height, as the smaller shield layers cause excessive temperature increase in the heating element, potentially resulting in deformation or breaking, especially when the area of the shield layers is reduced to minimize stray capacitance and power consumption.
Innovation Solution
A thin-film magnetic head design where the heating element has a portion with a lower resistance per unit length than other portions, allowing for controlled heat generation and distribution, with this portion being positioned between the electromagnetic coil and MR effect elements, and an inter-element shield layer is used to enhance heat management, ensuring the heating element's stability and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the area of shield layers is reduced to minimize stray capacitance and power consumption, then stray capacitance and power consumption are decreased, but the heating element experiences excessive temperature increase causing deformation or breaking
Solution Approach 1:
The heating element is designed with non-uniform resistance distribution, where the resistance per unit length varies at different positions. Specifically, the resistance per unit length is smaller in the region running off the shield layer compared to other regions. This local quality variation allows the heating element to generate less heat in the run-off portion, preventing excessive temperature increase and maintaining reliability while using smaller shield layers to reduce power consumption.
2Productivity
If the sheet resistance of the heating portion is increased to generate more heat for effective protrusion, then the protrusion efficiency is improved, but the temperature increase becomes excessive causing deformation or breaking
Solution Approach 1:
The heating element employs spatially varying resistance to achieve effective heating where needed while avoiding excessive temperature elsewhere. The resistance per unit length is deliberately made smaller in the run-off portion compared to other portions, creating a non-uniform heat distribution that promotes effective element protrusion while preventing thermal damage to the heating element itself.
3Loss of energy
If the total resistance of the heater is increased to reduce power consumption, then power consumption is reduced, but the current path becomes longer causing the heater to run off shield layers
Solution Approach 1:
The heating element is designed with spatially varying resistance properties. The resistance per unit length is smaller in the run-off portion compared to other portions, which allows the heater to achieve the required total resistance for low power consumption without excessively increasing the current path length. This controlled resistance variation prevents the heater from running off the shield layers while maintaining energy efficiency.
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 effectively suppresses excessive temperature increases in the heating element, preventing deformation and breaking, thereby maintaining the stability and reliability of the heating element even with smaller shield layers, ensuring consistent read and write performance.
Implementation Method 1
a heater is provided within a thin-film magnetic head, and the ends of the electromagnetic coil element and the MR effect element are protruded toward the magnetic disk due to the heat generated from the heater
Implementation Method 2
the shield layer is formed of a magnetic metal, and has larger heat conductivity compared to the surrounding insulating portions. Therefore, the shield layer is suitable for the heatsink of the heater
Implementation Method 3
the ends of the electromagnetic coil element and the MR effect element are protruded toward the magnetic disk due to the heat generated from the heater
Data Source
AI summary
Provided is a thin-film magnetic head having a heating element in which excessive increase in temperature is suppressed corresponding to smaller area of the shield layers of the MR effect element. The thin-film magnetic head comprises: an electromagnetic coil element; an MR effect element having two shield layers sandwiching an MR effect multilayer; and a heating element having a heating layer provided at least between the electromagnetic coil element and the MR effect element, and further in the head, at least a portion of a run-off portion of the heating layer running off the shield layer closer to the heating layer than the other shield layer has a resistance per unit length smaller than a resistance per unit length of the other portions than the portion running off the shield layer.