Self-Servo Writing Disk Drive Using Read Signal Gain Adjustment
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Solution Overview
Problem
External servo writers used for manufacturing data storage devices are expensive and require a clean room environment, making them a bottleneck in the manufacturing process, while existing self-servo writing methods are inefficient for writing concentric servo sectors.
Innovation Solution
A disk drive with internal control circuitry that generates and processes a read signal to detect servo seed patterns, adjusting amplifier gain and thresholds to accurately write concentric servo tracks independent of external writers, using a servo seed pattern that spans multiple disk revolutions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If external servo writers are used to write concentric servo sectors, then manufacturing precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The disk drive performs self-servo writing using its own internal servo system and control electronics to write concentric servo sectors, eliminating the need for external servo writers. The head positioning is achieved through the drive's own voice coil motor and servo control circuitry, allowing the system to service itself during manufacturing.
Solution Approach 2:
The invention extracts and removes the external servo writer from the manufacturing process entirely. By using the internal servo system of the disk drive itself to write the servo sectors, the complex external equipment is taken out of the system, simplifying the manufacturing process while maintaining precision.
2Manufacturing precision
If external servo writers are used to write concentric servo sectors, then manufacturing precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
The disk drive uses its internal servo system to write concentric servo sectors without requiring external equipment. This self-service capability allows the writing process to be performed in standard manufacturing environments without clean room requirements, significantly improving ease of manufacture.
Solution Approach 2:
The invention replaces expensive, complex external servo writer equipment with the disk drive's own existing servo system. This substitution eliminates the need for costly clean room facilities and specialized external writing equipment, making manufacturing more accessible and easier to implement.
3Reliability
If external servo writers are used, then reliability of servo sector writing is improved, but productivity deteriorates
Solution Approach 1:
The disk drive performs self-servo writing using its internal electronics and servo system, eliminating the sequential bottleneck created by external servo writers. Multiple drives can be manufactured simultaneously without requiring external equipment, significantly improving productivity while maintaining writing reliability through the drive's own control systems.
Solution Approach 2:
The invention segments the servo writing function from the external equipment and integrates it into each individual disk drive. This allows each drive to independently write its own servo sectors, enabling parallel manufacturing processes and eliminating the sequential dependency on external servo writers, thereby improving overall manufacturing throughput.
4Device complexity
If self-servo writing methods are used to write concentric servo sectors, then device complexity is reduced, but manufacturing precision deteriorates
Solution Approach 1:
The disk drive uses its own servo system to write concentric servo sectors with high precision. By leveraging the drive's existing voice coil motor, head positioning mechanics, and servo control electronics, the system achieves accurate concentric servo sector writing without requiring complex external equipment, maintaining both simplicity and precision.
Solution Approach 2:
The self-servo writing process uses the drive's own servo feedback mechanisms to monitor and adjust head position during the writing process. This closed-loop control ensures that concentric servo sectors are written with high precision despite using only internal system components, resolving the trade-off between complexity and precision.
Data Source
AI summary
A data storage device is disclosed comprising a disk comprising at least one servo seed pattern, and a head actuated over the disk. An amplitude measurement is generated based on a read signal emanating from the head while reading the disk. A number of times the amplitude measurement exceeds a first threshold is first counted during a first revolution of the disk, and a number of times the amplitude measurement exceeds the first threshold is second counted during a second revolution of the disk. The servo seed pattern is detected based on the first count and the second count.