Magnetic Head Anti-High Temperature Testing via Acute Angle Field
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Solution Overview
Problem
Conventional methods for testing the anti-high temperature performance of magnetic heads are limited in sensitivity and cannot effectively screen out defective heads without heating, especially when a heating element is not present, and fail to detect all defective heads using common magnetization methods.
Innovation Solution
Applying a plurality of magnetic fields with different intensities in specific directions to a magnetic head with shielding layers and measuring output parameter curves to identify variations beyond allowable values, without heating the magnetic head, by using a second magnetic field direction passing through the ABS at an acute angle to the ABS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional magnetization methods (common magnetization direction or perpendicular to ABS) are used for testing, then the testing process is simple, but the sensitivity for detecting anti-high temperature performance defects is insufficient
Solution Approach 1:
The patent changes the magnetic field direction parameter from conventional directions (common magnetization direction or perpendicular to ABS) to a specific acute angle direction relative to the ABS. This parameter change enables the magnetic field to interact with the MR element at an optimized angle, significantly improving detection sensitivity for anti-high temperature performance defects while maintaining a relatively simple testing procedure
Solution Approach 2:
The patent introduces a new dimensional perspective by applying the magnetic field at an acute angle to the ABS rather than in the conventional directions. This angular dimension provides a new testing dimension that reveals defects invisible to conventional methods, enhancing measurement precision without substantially increasing device complexity
2Reliability
If heating elements are used to apply high temperature for testing, then anti-high temperature performance can be tested, but the testing apparatus becomes more complex and may damage non-defective heads
Solution Approach 1:
The patent replaces the thermal testing mechanism (heating elements) with a magnetic field-based testing mechanism. By applying magnetic fields at a specific acute angle to the ABS, the testing method detects anti-high temperature performance defects through magnetic response characteristics without subjecting the magnetic head to high temperature, thereby eliminating thermal damage risk while maintaining reliable defect detection
Solution Approach 2:
The patent uses the magnetic field as an intermediary to indirectly assess anti-high temperature performance. Instead of directly applying heat and observing thermal effects, the magnetic field serves as a mediator that interacts with the MR element's magnetic properties, which are affected by thermal stress history, enabling non-destructive detection of temperature-related defects
3Measurement precision
If multiple magnetic field directions are applied to improve detection accuracy, then measurement precision improves, but testing time increases
Solution Approach 1:
The patent optimizes the magnetic field direction parameter by selecting a specific acute angle relative to the ABS that maximizes defect detection sensitivity. This optimized parameter selection achieves high measurement precision with a single magnetic field direction, avoiding the time penalty associated with testing multiple directions while maintaining superior detection accuracy compared to conventional directions
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 allows for the reliable detection and screening of defective magnetic heads with poor anti-high temperature performance at room temperature, improving testing precision and identifying defects that conventional methods miss, without damaging non-defective heads.
Implementation Method 1
the resistance of the MR element varies with the changes of an external magnetic field, which results in variation in the output of the MR read head
Data Source
AI summary
A method of testing anti-high temperature performance of a magnetic head comprises applying a plurality of second magnetic fields with different intensities in a second direction to the magnetic head, and measuring a second output parameter curve, and judging whether a variation that is beyond an allowable value is presented on the second output parameter curve, therein the second direction passes through the ABS and at an angle whose absolute value is an acute angle to the ABS. The present invention can screen out defective magnetic heads that possess poor anti-high temperature performance without heating the magnetic head.