Method and system for measuring fly height
AssigneeSeagate Technology LLC
InventorsSerge Jacques Fayeulle, Paul W. Smith
Life of this patent
Estimating the term…
Abstract
A system and method for measuring the fly height of a head flying over a disc in a disc drive is disclosed. A head is vertically spaced from a rotating disc surface by an air bearing surface. The disc has one or more radial grooves in the surface of the disc. As the disc rotates, the radial grooves on the disc pass under the head and induce a perturbation in the signal. By measuring the perturbations in the signal caused by the grooves in the disc surface, and by processing the measurement signal, a vertical spacing signal proportional to the vertical spacing between the disc and the head can be obtained.
Claims19
A measurement system for determining the fly height of a head in a disc system, said device comprising:
- a disc having one or more radial grooves patterned in the disc surface;
- a head for reading a signal generated when the disc is rotating;
- and
- a signal processing circuit for processing an electrical measurement signal to produce a vertical spacing signal proportional to the vertical spacing between the one or more grooves and the head, wherein the electrical measurement signal is generated when the head passes over each of the one or more grooves.
A method for determining fly height in a system having a head flying over a rotating disc, wherein the rotating disc has at least one radial groove, the method comprising the steps of:
- measuring a first pulse width of a first signal when the head is flying over the disc in a region not containing a radial groove;
- measuring a second pulse width of a second signal when the head has passed over a groove;
- comparing the ratio of the pulse widths to determine the height the head is flying over the disc.
A fly height measurement system comprising:
- a disc drive including a spindle hub securing a data storage disc, the data storage disc having at least one radial groove in a surface of the disc, the disc drive further including a head disposed adjacent the surface;
- and
- measuring means for determining the fly height between the head and the disc surface utilizing a radial groove.
Dependencies are inferred from the claim text.