Patent ID: 7663829
Filing Date: 2010-02-16
Classification: G11B

Abstract:
1. A method for testing a performance of a head gimbal assembly including a magnetic head and a micro-actuator for precisely positioning the magnetic head with respect to a magnetic medium, the method comprising steps of: (1) writing an initial track of information onto the magnetic medium, reading out the initial track of information, measuring an initial track average amplitude profile of the read-out initial track information, and calculating a track center value OFFSET (2) judging whether an operating direct current voltage to be applied to the micro-actuator is higher than a threshold value or not, if NO, performing steps (3)-(6), if YES, performing steps (7)-(9); (3) moving the magnetic head toward an off-track direction by a predetermined distance D; (4) applying the operating direct current voltage to the micro-actuator to drive the micro-actuator displacement in a positive direction and simultaneously writing a first track of information onto the magnetic medium, reading out the first track of information, measuring a first track average amplitude profile of the read-out first track of information, and calculating a track center value OFFSET (5) applying the operating direct current voltage to the micro-actuator to drive the micro-actuator displacement in a negative direction and simultaneously writing a second track of information onto the magnetic medium, reading out the second track of information, measuring a second track average amplitude profile of the read-out second track of information, and calculating a track center value OFFSET (6) calculating the displacement of the micro-actuator according to a formula, the formula being ((OFFSET (7) applying the operating direct current voltage to the micro-actuator to drive the micro-actuator displacement in a positive direction and simultaneously writing a first track of information onto the magnetic medium, reading out the first track of information, measuring a first track average amplitude profile of the read-out first track of information, and calculating a track center value OFFSET (8) applying the operating direct current voltage to the micro-actuator to drive the micro-actuator displacement in a negative direction and simultaneously writing a second track of information onto the magnetic medium, reading out the second track of information, measuring a second track average amplitude profile of the read-out second track of information, and calculating a track center value OFFSET (9) calculating the displacement of the micro-actuator according to a formula, the formula being (OFFSET