Patent ID: 7372254

Claim:
A method comprising: using a force detecting element to move a moving coil part linearly, which moving coil part is formed without ferromagnetic materials; driving said moving coil part with a driving signal, and detecting an induced signal on a stationary coil part which is formed without ferromagnetic materials, to produce an output signal indicative of a moving relationship between said moving coil part and said stationary coil part, said stationary coil part sufficiently close to said moving coil part such that magnetic flux from said moving coil part induces a current in said stationary coil part; and using said output signal to detect information from said force detecting element indicative of a resolution in detection of relative positions of said coil parts in range of microns or less than microns, wherein said using said output signal to detect information comprises synchronously detecting the output signal using a multiplier reference signal, where said synchronously detecting is synchronized relative to said drive signal by adjusting a relative phase between said drive signal and said multiplier reference signal, and multiplying said output signal using said multiplier reference signal.