APPARATUS AND METHOD FOR MEASURING ANGLE

摘要

Light outputted from a collimator lens is diffracted into light of a different order by a transmission grating, the diffracted light is applied on a flat plane of an object to be measured and is reflected by the flat plane of the object to be measured. Then, the light which passed through the transmission grating again is permitted to form an image at a position away from the optical axis of the outgoing light, and the angle of the object to be measured to the optical axis of the collimator lens is measured, based on the image position and the order of the image formed light. Thus, angles in a wide range can be measured at a high resolution.