Active control of a read/write head

Abstract

The invention generally relates to hard disk drives with a disk and a read/write head, and methods for preventing contact between the disk and the read/write head. The hard disk drive includes a z-axis actuator configured to control movement of the read/write head, and to prevent contact between the read/write head and the disk, based on signals from a controller that indicate when the distance between the read/write head and the disk are outside a predetermined range, such as between 0 and 10.0 nm.

1 . A hard disk drive comprising:
 a disk comprising a magnetic data recording and reading surface;   a read/write head for reading data from and writing data to the disk surface;   a z-axis actuator coupled to the head for controlling movement of the head in a substantially orthogonal direction relative to the disk surface; and   a controller for monitoring a distance of the head relative to the disk surface and for maintaining the distance within a predetermined range;   wherein one or both of the disk surface and the head comprises a significantly small amount of overcoat or lubricant layer.   
     
     
         2 . The hard disk drive of  claim 1  wherein the robust control actively controls the head within a tolerance of between 1.0 nm and 10.0 nm. 
     
     
         3 . The hard disk drive of  claim 1  wherein the robust control comprises monitoring head-media spacing (HMS) between the head and the disk surface and also transmitting signals to the z-axis actuator to cause movement of the head. 
     
     
         4 . The hard disk drive of  claim 1  wherein the robust control comprises a servomechanism with error-sensing negative feedback to maintain the head within a range of 1.0 nm and 10.0 nm. 
     
     
         5 . The hard disk drive of  claim 1  wherein the z-axis actuator is rigidly coupled to the head. 
     
     
         6 - 25 . (canceled) 
     
     
         26 . The hard disk drive of  claim 1  wherein the overcoat or lubricant layer has a thickness of between 0.1 nm and 2.0 nm. 
     
     
         27 . The hard disk drive of  claim 1  wherein the overcoat or lubricant layer has a thickness of between 0.35 nm and 1.0 nm.