Magnetic Head Laser Heating for Height Control
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Solution Overview
Problem
Existing hard disk drive technologies face challenges in accurately controlling the heights of read and write heads, which affects the normal reading and writing of storage media due to technical limitations in the wafering process.
Innovation Solution
The method involves using laser heating-induced compensation, where a laser irradiation device is used to thermally expand the read and write heads, followed by lapping to adjust their heights, ensuring they meet target values for optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the wafering process is used to manufacture the magnetic head, then the read head and write head can be cemented inside the magnetic head, but the heights of the read head and write head cannot be precisely controlled to meet target values
Solution Approach 1:
The patent applies preliminary action by performing laser heating on the substrate before the lapping process. This pre-heating causes thermal expansion of the read head and write head, creating a compensated state that anticipates the material removal during lapping. By preparing the workpiece in advance with thermal expansion, the final heights after lapping can precisely meet target values, resolving the contradiction between ease of manufacture and manufacturing precision.
Solution Approach 2:
The patent changes physical parameters by controlling the temperature of the substrate through laser heating. By adjusting the heating parameters, the read head and write head expand to specific degrees, which compensates for the material removal that will occur during lapping. This parameter change approach enables precise control of final head heights, transforming the manufacturing process from one with poor height control to one achieving nanometer-level precision.
2Manufacturing precision
If conventional lapping is used to adjust head heights, then the lapping process can be performed, but nanometer-level height control in small distances cannot be achieved
Solution Approach 1:
The patent directly applies thermal expansion by using laser heating to expand the read head and write head before lapping. The controlled thermal expansion creates a compensatory effect that, when combined with the lapping process, achieves nanometer-level height control. This thermal expansion principle transforms the lapping process from one incapable of nanometer-level control to one that can precisely achieve target heights.
Solution Approach 2:
The patent introduces thermal expansion as an intermediary mechanism between the lapping process and the final head height. The laser heating acts as a mediator that modifies the dimensions of the read head and write head, creating a compensated state that enables the subsequent lapping process to achieve precise nanometer-level control. This intermediary approach bridges the gap between conventional lapping and nanometer-level precision requirements.
3Ease of manufacture
If the read head and write head heights are not precisely controlled, then the magnetic head can be manufactured, but normal reading and writing of the storage medium cannot be ensured
Solution Approach 1:
The patent applies preliminary action by performing laser heating-induced thermal expansion before the lapping process. This pre-compensation ensures that when material is removed during lapping, the final heights of the read head and write head precisely meet target values, thereby ensuring reliable reading and writing functions while maintaining manufacturing feasibility.
Solution Approach 2:
The patent changes the temperature parameter of the substrate through laser heating, which causes dimensional changes in the read head and write head. This parameter change enables precise control of final head heights after lapping, ensuring both manufacturability and reliable reading/writing functionality of the storage medium.
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 precise control of read and write head heights, enabling improved reading and writing capabilities by overcoming the limitations of current lapping techniques that struggle with nanometer-level height control in small distances.
Implementation Method 1
irradiating at a fixed point proximate to the read/write part with a laser irradiation device until the read head and the write head are thermally expanded
Implementation Method 2
the read head and the write head are thermally expanded
Data Source
AI summary
The present disclosure discloses a magnetic head, a head gimbal assembly, a hard disk drive, and a method for processing a magnetic head. The method comprises irradiating at a fixed point proximal to the read/write part with a laser irradiation device until the read head and the write head are thermally expanded; orientating air bearing surfaces of a plurality of magnetic heads forming a magnetic strip toward a lapping surface of a lapping device after laser irradiation, holding the air bearing surfaces in place, lapping with the lapping device until the air bearing surfaces are coplanar; and disassembling the magnetic strip to obtain a lapped magnetic head. Through laser heating induced compensation, the heights of lapped read head and write head of the magnetic head meet their respective target values, ensuring the normal reading and writing of the storage medium of the magnetic disk.