Granted Patent B1

US 7,796,356 · App. 12/435,280 · Granted Sep 14, 2010

Abstract

Claims (30)

1. A disk drive comprising:

a slider;

media;

a head residing on the slider and having an air-bearing surface (ABS), the head further including a touchdown sensor proximate to the ABS, the touchdown sensor being capable of detecting a temperature change of 0.1 degree Celsius; and

touchdown sensor control circuitry coupled with the touchdown sensor, the touchdown sensor control circuitry for driving a current through the touchdown sensor and converting a signal from the touchdown sensor into an indication of whether touchdown has occurred.

2. The disk drive of claim 1 wherein the touchdown sensor is a thermistor.

3. The disk drive of claim 2 wherein the touchdown sensor includes a metal.

4. The disk drive of claim 2 wherein the touchdown sensor includes a first metal layer, and a second metal layer, a portion of the at least one amorphous semiconductor residing between a portion of the first metal layer and a portion of the second metal layer.

5. The disk drive of claim 1 wherein the touchdown sensor includes at least one amorphous semiconductor.

6. The disk drive of claim 5 wherein the at least one amorphous semiconductor includes at least one of Ge, Si, GeSi, and GeSiO.

7. The disk drive of claim 1 wherein the touchdown sensor is capable of detecting the temperature change of 0.01 degree Celsius.

8. The disk drive of claim 1 wherein the touchdown sensor has a lateral dimension of not more than fifty microns.

9. The disk drive of claim 8 wherein the lateral dimension is not more than one micron.

10. The disk drive of claim 1 wherein the touchdown sensor has a thickness of not more than five hundred nanometers.

11. The disk drive of claim 1 wherein the touchdown sensor has a negative thermal coefficient of resistivity.

12. The disk drive of claim 1 wherein the touchdown sensor has a positive thermal coefficient of resistivity.

13. A disk drive comprising:

a slider;

media;

a head residing on the slider and having an air-bearing surface (ABS), the head further including a touchdown sensor proximate to the ABS, the touchdown sensor being capable of detecting a temperature change of 0.1 degree Celsius, the touchdown sensor including at least one of amorphous Ge, amorphous Si, amorphous GeSi, and amorphous GeSiO and having a lateral dimension of not more than one micron and a thickness of not more than four hundred nanometers; and

touchdown sensor control circuitry coupled with the touchdown sensor, the touchdown sensor control circuitry for driving a current through the touchdown sensor and converting a signal from the touchdown sensor into an indication of whether touchdown has occurred.

14. A method for detecting a touchdown of a head having an air-bearing surface (ABS) on a medium, the method comprising:

determining a first temperature of a touchdown sensor integrated in the head, the touchdown sensor being proximate to the ABS, the touchdown sensor capable of detecting a temperature change of 0.1 degree;

determining a second temperature of the touchdown sensor;

calculating a difference between the first temperature and the second temperature; and

detecting the touchdown based on the difference.

15. The method of claim 14 wherein the step of detecting further includes:

detecting the touchdown if the difference is at least a threshold.

16. The method of claim 14 wherein the step of detecting further includes:

detecting the touchdown if a change in a rate of change of temperature is at least a threshold.

Assignments (8)