| 摘要 |
PROBLEM TO BE SOLVED: To provide a position detector small in both of an optical axis direction and an optical axis orthogonal direction.SOLUTION: A position detector includes: a first member; a second member rotatable around an optical axis in relation to the first member; a first detection device for outputting a first signal and a second signal according to the position of the second member; a second detection device which is disposed on the same plane as that of the first detection device and in a phase different from that of the first detection device, in a plane orthogonal to the optical axis, and outputs a third signal according to the position of the second member; and arithmetic means for mutually synchronizing a low-order signal obtained by performing arc tangent calculation using the first signal or the second signal, an intermediate-order signal obtained by performing vernier calculation after performing each arc tangent calculation using the first signal and the second signal and a high-order signal obtained from the third signal to calculate the position of the second member in relation to the first member. |
