Thin Film Magnetic Head Protrusion Control via Parallel Thermistor
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Solution Overview
Problem
The variation in protrusion of the element portion in thin film magnetic heads due to external environmental temperature fluctuations poses a risk of contact with the recording medium, as the amount of heat generated by the heater is insufficient to maintain consistent gap distances, leading to unreliable recording and reproducing characteristics.
Innovation Solution
Incorporating a temperature correcting resistor with a negative resistance temperature coefficient connected in parallel to the heater, which adjusts the current flow based on environmental temperature, thereby controlling the heat generated and maintaining consistent protrusion of the element portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the heater generates heat to expand the reproducing element and recording element toward the recording medium, then the gap between the recording medium and element portion is narrowed improving recording and reproducing characteristics, but the element portion may come into contact with the recording medium when external environmental temperature is high causing damage
Solution Approach 1:
The patent implements a feedback control system using a temperature sensor to detect the temperature of the reproducing element and recording element, and a control circuit to adjust the heater power accordingly. When the temperature increases (causing thermal expansion and potential contact), the control circuit reduces heater power to compensate. This closed-loop feedback mechanism maintains the gap distance within a safe range while preventing contact damage.
Solution Approach 2:
The patent dynamically changes the operational parameters (heater power, temperature) based on environmental conditions. By monitoring temperature and adjusting heater power in real-time, the system adapts to varying external environmental temperatures, maintaining optimal gap distance without causing contact. This parameter adjustment resolves the contradiction between utilizing thermal expansion for gap control and preventing contact damage.
2Reliability
If the amount of heat generated from the heater is reduced to reduce thermal expansion of the element portion, then the risk of contact with recording medium is reduced, but the gap narrowing effect is insufficient resulting in low recording and reproducing characteristics
Solution Approach 1:
The feedback control system continuously monitors temperature and gap distance, adjusting heater power to achieve the optimal balance. When contact risk is detected, the system reduces heat generation to prevent damage. When safe operating conditions exist, the system increases heat generation to achieve adequate gap narrowing for improved recording characteristics. This dynamic adjustment resolves the contradiction between contact prevention and gap narrowing effectiveness.
Solution Approach 2:
The patent transitions from a static heater power approach to a dynamic control system that continuously adjusts heater power based on real-time temperature and gap distance measurements. This dynamic adjustment allows the system to optimize the balance between preventing contact damage and achieving sufficient gap narrowing for high-quality recording and reproducing operations.
3Adaptability or versatility
If the amount of protrusion of the element portion varies according to external environmental temperature, then the gap between element portion and recording medium varies, but recording and reproducing characteristics become unreliable
Solution Approach 1:
The temperature sensor and control circuit form a feedback loop that detects external environmental temperature changes and compensates for their effect on gap distance. When external temperature increases causing excessive protrusion, the system reduces heater power to maintain consistent gap distance. This feedback mechanism ensures reliable recording and reproducing characteristics across varying environmental temperatures.
Solution Approach 2:
The system takes preliminary action by detecting temperature trends and adjusting heater power before contact or excessive gap variation occurs. The control circuit proactively compensates for thermal expansion effects by reducing heater power when temperature rises, preventing gap inconsistency before it affects recording reliability.
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 solution ensures that the variation in protrusion of the element portion is minimized across different environmental temperatures, preventing contact with the recording medium and maintaining reliable recording and reproducing characteristics by automatically adjusting the current through the heater.
Implementation Method 1
a heater that is supplied with power and generates heat
Implementation Method 2
a temperature correcting resistor that is connected in parallel to the heater and has a negative resistance temperature coefficient
Implementation Method 3
a reproducing element that reads out magnetic recording information from a recording medium using magnetoresistance
Data Source
AI summary
A thin film magnetic head is disclosed that is capable of preventing the contact between an element portion and a recording medium and a variation in the amount of protrusion of the element portion. A thin film magnetic head includes: a reproducing element; a recording element that is formed on the reproducing element; a heater that is supplied with power and generates heat to expand at least one of the reproducing element and the recording element such that the reproducing element and/or the recording element protrude toward a recording medium; and a temperature correcting resistor that is connected in parallel to the heater and has a negative resistance temperature coefficient.