The dual stage actuation (DSA) is one of the most attractive methods for increasing the track density of hard disk drives (HDDs). We have developed a φ-shaped actuated suspension as a fine actuator for a DSA system. The developed suspension's main resonance frequency was higher than 9 kHz, its generated displacement was larger that 1e-6 m at an applied voltage of 30 V and its shock resistance was greater than 3000 G. Flying-height variance caused by DSA driving (+/- 22 V) was less than 1.3 % of nominal flying-height. The decrease of displacement was almost constant, less than 5 % after 1e9 driving-cycles under heavy conditions (+/- 30V at 100℃, +/- 30V at 85℃ and 85% humidity). Based on these data, we concluded that our actuated suspension can maintain a stable flying-height during its operation and its lifetime is as long as other actuators for HDDs.
