Hardware Reference
In-Depth Information
uses a single crystal silicon electrostatic comb drive microactuator mounted be-
tween the slider and suspension. It drives the slider on which a magnetic head
element is attached. Figure 3.66 shows a quarter of the actuator which consists
of a movable rotor connected to an anchored central column via electrical con-
ductive silicon spring beams, and a stator connected to the silicon substrate by
a bus bar which electrically isolates the stator from the rotor. The stator and
rotor of the microactuator are suspended and directly processed from a highly
N-doped single crystal silicon substrate. The dimension of the microactuator
is 1.4 mm × 1.4 mm × 0.18 mm.
Figure 3.65: Schematic of microactuator driving slider.
Figure 3.66: View of one quarter of the microactuator.
The parallel plate pairs attached to the stator and rotor generate electro-
static force. For small rotational angles θ, these plate pairs may be modeled
as parallel plate capacitors separated by gaps. The torque T with a driving
voltage V to half of the structure is given by
µ
¶
2
V
x
n
−Rθ
T ∝ RA
,
(3.140)
