Glass Substrate Ski Jump Slope Control for Head Crash Prevention
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Solution Overview
Problem
Conventional glass substrates for magnetic disks fail to ensure stable floating of magnetic head sliders due to sharp changes in the ski jump slope, leading to potential head crashes during load/unload operations, despite conventional techniques for forming ski jumps to prevent direct contact.
Innovation Solution
A glass substrate with a ski jump design featuring a rate of change of angles of tangents to the slope in the radial direction of less than 10/W μrad/mm and a height deviation of less than 25% from the average, preventing the magnetic head slider from hitting the main surface by ensuring a stable floating trajectory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a ski jump is formed on the glass substrate to prevent direct contact between the magnetic head slider and the recording zone, then the recording zone can be expanded, but the magnetic head slider may still come into contact with the main surface during load/unload operations, leading to head crash
Solution Approach 1:
The invention changes the geometric parameters of the ski jump slope by controlling the rate of change of tangent angles to be equal to or less than 10/W μrad/mm. This parameter optimization ensures that the magnetic head slider can smoothly traverse the ski jump during load/unload operations without experiencing abrupt directional changes that would cause contact with the main surface, thereby maintaining stable floating while preserving the expanded recording zone.
2Ease of operation
If the slope of the ski jump is made steeper to reduce the initial floating area, then the magnetic head slider can be directed away from the recording zone more effectively, but the rate of change of tangent angles increases, causing the magnetic head slider to hit the main surface
Solution Approach 1:
The invention optimizes the slope parameters of the ski jump by precisely controlling the rate of change of tangent angles. Rather than making the slope steeper, the invention finds the optimal balance where the slope is sufficiently inclined to guide the magnetic head slider away from the recording zone during loading, while the rate of change of tangent angles remains equal to or less than 10/W μrad/mm to prevent the slider from hitting the main surface, thus resolving the contradiction between ease of operation and reliability.
3Ease of manufacture
If conventional ski jump formation techniques are used, then the manufacturing process remains simple, but the flatness of the slope is insufficient, causing unstable floating of the magnetic head slider
Solution Approach 1:
The invention specifies precise parameter ranges for the ski jump slope, requiring the rate of change of tangent angles to be equal to or less than 10/W μrad/mm. This parameter specification provides clear manufacturing targets that balance ease of manufacture with the required precision for stable magnetic head slider floating, transforming the vague requirement of 'improved flatness' into a quantifiable and manufacturable specification.
Data Source
AI summary
A main surface of a glass substrate for a magnetic disk is disk-shaped and has a ski jump on an outer peripheral end portion of the main surface opposing a magnetic head slider to be loaded. A rate of change of angles of tangents to a slope of the ski jump in a radial direction in a range between an inner circumferential side and a transition point on the slope is equal to or less than 10/W μrad/mm where W is a width of the magnetic head slider.