Patent ID: 7808656

Claim:
A displacement sensor, comprising: a. a light source that generates a beam of light; b. a displacement structure having a first surface, a probe depending outwardly therefrom, and an oppositely-disposed reflection surface that is changed when the probe interacts with the object, the reflection surface disposed so as to interact with the beam of light and so that a reflected beam reflects from the reflection surface, a characteristic of the reflected beam indicative of a state of the probe; c. a two-dimensional diffraction grating disposed between the light source and the reflection surface so that at least one diffracted beam is created by the diffraction grating; d. a first annular photon detector disposed between the light source and the diffraction grating, the first annular photon detector defining a first hole passing therethrough, the first hole having a diameter corresponding to a diameter of a light beam directed to the reflection surface, the first annular photon detector including a plurality of spaced-apart first photosensitive segments, each of the first photosensitive segments being responsive to a quality of the reflected beam; and e. a second annular photon detector disposed between the first annular photon detector and the diffraction grating, the second annular photon detector defining a second hole passing therethrough, the second hole having a diameter sufficient to allow the reflected beam to pass therethrough, the second annular photon detector including a plurality of spaced-apart second photosensitive segments, each of the second photosensitive segments being responsive to a quality of the diffracted beam.