Optical micrometer measuring system

Claim 1

An optical micrometer measuring system adapted to gauge minute distances between spaced points on an object under test, said system comprising: A. a stage for supporting the object; B. an objective disposed above said stage and having a vertical optical axis; C. a beam-splitting element disposed above said objective and having an interface inclined relative to said vertical axis; D. a semi-reflective mirror interposed between said objective and said element; E. means including an object light source to illuminate said object to produce object-modulated rays which are directed by said objective upwardly through said mirror onto said element interface, the rays being deflected by said interface toward a main optical path to create in the real image plane of said objective an aerial object image; F. an eyepiece disposed in said main path to provide an operator with a magnified view of the object image; G. a pointer image projector including a projector light source whose rays are masked by a mask component having a shaped aperture which defines the geometry of the pointer and are projected by a projection lens component to produce pointer-modulated rays; H. means directing said pointer-modulated rays from the projector downwardly through the element toward the mirror to be reflected upwardly thereby to impinge on the interface and to be deflected thereby along the main optical path toward the real image plane to produce a pointer image thereon which is superimposed over the object image; and I. micrometer means operatively coupled to said projector to laterally displace the pointer image to transverse the distance between any two spaced points on the object image and to indicate said distance.