Adaptive HAMR laser power data storage device

Patent metadata

Field	Value
Publication number	US-9478248-B2
Application number	US-201414512590-A
Country	US
Kind code	B2
Filing date	Oct 13, 2014
Priority date	Aug 22, 2014
Publication date	Oct 25, 2016
Grant date	Oct 25, 2016

Abstract

A data storage device and associated methods may provide at least a data storage medium that is separated from a heat assisted magnetic recording data writer and is connected to a controller. The controller can be configured to change a laser power of the heat assisted magnetic recording data writer in response to a tested bit error rate of a median data track of a plurality of adjacent data tracks reaching an identified threshold.

First claim

What is claimed is:

1. An apparatus comprising a data storage medium separated from a heat assisted magnetic recording (HAMR) data writer connected to a controller configured to change a laser power of the HAMR data writer and predict a lifespan of a near-field transducer portion of the HAMR data writer in response to a tested bit error rate (BER) of a median data track reaching an identified threshold, the tested BER corresponding to writing a common test pattern to a first data track more than twice, the first data track being immediately adjacent to the median data track.

2. The apparatus of claim 1 , wherein the identified threshold is a point at which the tested BER changes from a decreasing trend to an increasing trend.

3. The apparatus of claim 2 , wherein the increasing and decreasing trends each correspond with a plurality of tested BER for the median data track over a plurality of different laser powers.

4. The apparatus of claim 1 , wherein the controller is connected to a laser power optimization circuit configured to attain the tested BER from a read channel of the HAMR data writer.

5. The apparatus of claim 1 , wherein the controller sets a laser maximum value in response to the tested BER reaching the identified threshold.

6. The apparatus of claim 5 , wherein the laser power is less than the laser maximum value.

7. The apparatus of claim 5 , wherein the controller restricts a laser of the HAMR data writer from experiencing a laser power value greater than the laser maximum value.

8. The apparatus of claim 1 , wherein the controller halts a testing routine in response to the identified threshold being reached.

9. The apparatus of claim 1 , wherein the controller calculates a plurality of different tested BER for a plurality of power values delivered to a laser of the HAMR data writer.

10. The apparatus of claim 1 , wherein the controller writes data to first and second data tracks positioned immediately adjacent the median data track prior to testing for the tested BER.

11. A method comprising:
positioning a heat assisted magnetic recording (HAMR) data writer separate from a data storage medium;
writing data to a median data track;
programming a common test pattern to an adjacent data track more than once, the adjacent data track positioned immediately adjacent the median data track;
testing the HAMR data writer with a controller to obtain a plurality of tested bit error rates (BER) respectively corresponding to a plurality of different laser power values;
identifying a predetermined threshold in the plurality of tested BER;
selecting a laser power value from the plurality of tested BER; and
predicting a lifespan of a near-field transducer with the controller after selecting the laser power value.

12. The method of claim 11 , wherein the predetermined threshold corresponds with a threshold laser power value where the tested BER switches from a decreasing trend to an increasing trend.

13. The method of claim 12 , wherein the selected laser power is less than the threshold power value.

14. The method of claim 11 , wherein the controller halts the testing of the HAMR data writer in response one of the plurality of tested BER reaching the predetermined threshold.

15. The method of claim 11 , wherein the controller identifies a lowest tested BER for the plurality of different laser power values, the selected laser power value being different than the lowest tested BER.

16. The method of claim 11 , wherein the adjacent data track is programmed with the common test pattern five times or more.

17. The method of claim 11 , wherein the controller selects the laser power value to minimize risk of thermal erasure conditions.

18. A method comprising:
connecting a controller to a heat assisted magnetic recording (HAMR) data writer a separated from a data storage medium, the HAMR data writer comprising a laser and a near-field transducer;
writing a common test pattern to at least first and second data tracks of the data storage medium, the first and second data track each being immediately adjacent a median data track;
testing the HAMR data writer with a plurality of different laser powers to obtain a plurality of tested bit error rates (BER);
altering a default laser power to an optimized laser power in response to the plurality of tested BER reaching a predetermined threshold where a tested BER trend switches from a negative slope to a positive slope;
predicting a lifespan of a near-field transducer with the controller after selecting the laser power value; and
writing user data to the median data track by heating the data storage medium with the optimized laser power.

19. The method of claim 18 , wherein the controller immediately stops the testing step and sets a maximum laser power in response to the predetermined threshold being reached.

Assignees

• Seagate Technology Llc

Inventors

• Cordle Michael A
• Martens Franklin P
• Chu Alfredo Sam
• Silewski Shawn Stephen
• Rausch Tim

Classifications

• G11B20/1816

  Testing · CPC title

• G11B5/6088

  Optical waveguide in or on flying head · CPC title

• G11B2005/0021

  Thermally assisted recording using an auxiliary energy source for heating the recording layer locally to assist the magnetization reversal · CPC title

• G11B19/048

  Testing of disk drives, e.g. to detect defects or prevent sudden failure · CPC title

• G11B20/10388 Primary

  control of the read or write heads, e.g. tracking errors, defocus or tilt compensation · CPC title