JPS5790102A - High-sensitive linear meter - Google Patents

Abstract

PURPOSE:To readily realize real time interference and to make possible high precision displacement measurement by a method wherein an interference stripe with a uniform tilt angle is allowed to be produced in company with the displacement of a movable object within a plane at a right angle to the optical axis of reference light in a machine tool, etc. CONSTITUTION:An optical element 32 capable of activating object light and reference light, and a hologram 23 formed with the object light and reference light at the standard position of the object are arranged on a movable object 22 which is movable along a fixed object. Prisms 33, 34 are installed on the fixed object, the prisms being used to turn round a light channel within the light channel between the element 32 and the hologram 23. Followed by this is the generation of an interference stripe with a uniform tilt angle including data on a direction lag and its amount as the tilt angle of the stripe and a space between them, the lag being relative to the wave surface of the object light from the wave surface of a regenerated image from the hologram 23, and the element 32 in company with the displacement of the movable object 22 within a plane at a right angle to the optical axis of the reference light. In addition, one or two components of the displacement in the plane vertical to the optical axis of the reference light are detected by measuring the tilt angle of the interference stripe and the space.