Disk Head Heater Control for Flying Height Noise Timing
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Solution Overview
Problem
Existing disk devices face challenges in properly controlling the flying height of the head above the disk medium due to thermal expansion, leading to noise and interference during read operations.
Innovation Solution
The disk device incorporates a heater to adjust the protrusion amount of the head through thermal expansion, utilizing a controller to detect noise during heating and adjust the read start timing or select alternative read elements to mitigate noise, ensuring proper flying height control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the heater is supplied with electric power to adjust the protrusion amount of the head through thermal expansion, then the flying height control is improved, but noise is generated during the heating process
Solution Approach 1:
The controller detects noise during the heating process and adjusts the read start timing in advance to avoid the noise period. By performing the read operation after the noise subsides, the system maintains flying height control while eliminating noise interference in the read signal.
Solution Approach 2:
The noise generated during heating is used as a detection signal to determine when the heating is complete. The controller monitors the noise level and uses its cessation as an indicator to start the read operation, converting the harmful noise into a useful timing reference.
2Productivity
If the read operation is performed immediately after heating starts, then the productivity is improved, but the read accuracy deteriorates due to noise interference
Solution Approach 1:
The controller performs a preliminary detection phase during heating to identify noise characteristics, then schedules the read operation for the period after noise subsides. This preliminary action ensures both efficient timing and high read accuracy.
Solution Approach 2:
The system dynamically adjusts the read start timing based on the actual noise conditions observed during heating. Rather than using a fixed delay, the controller adapts the read timing to match the specific heating characteristics, optimizing both speed and accuracy for each operation.
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 effectively reduces noise interference by adjusting the read start timing and selecting appropriate read elements, thereby improving the accuracy and reliability of read operations.
Implementation Method 1
the head is equipped with a heater, which is to be supplied with an electric power to adjust the protrusion amount of the head due to thermal expansion and to control the flying height of the head above the disk medium
Data Source
AI summary
According to one embodiment, a disk device includes a disk medium, a head, and a controller. The disk medium includes a recording surface. The head includes a first read element and a heater. The first read element faces the recording surface. The controller is configured to detect a first noise during heating of the head, in response to a signal read from the disk medium by the first read element when starting supply of an electric power to the heater.