Interferometric non-contact optical probe and measurement

摘要

A non-contact optical probe utilizes an optical reference surface that projects a curved test wavefront toward the test surface and detects it by creating curved interferometric fringes localized in space in front of the reference surface. When a point to be measured on the test surface intersects the location of the fringes, the condition is detected by the probe. Because the fringes are localized at a known position in space with respect to a reference system, the precise coordinate of the surface point can be established. Such localized fringes are preferably produced by a spectrally controllable light source. The curvature of the fringes ensures a sufficiently large angle of acceptance for the probe to capture light reflected from points of high surface slope. The probe is particularly suitable for coordinate measurement machines.

主权项

1. An interferometric measurement method comprising the steps of:
providing a light source and an interferometric probe configured to project a test wavefront adapted to produce curved localized fringes when a test surface is placed at a predetermined position in space relative to a reference surface; determining a position of a single point of interest on a test surface relative to a reference coordinate system by fringe analysis when the point intersects said curved localized fringes; and repeating said determining step for a plurality of single points along a predetermined scanning pattern.