Patent ID: 7027141

Claim:
An optical measurement device for determining the planar orientation of a surface, the device comprising: a focusing lens having a focal axis and a focal point positioned on the focal axis, the focusing lens being positioned between the focal point of the lens and a detector operatively positioned on the focal axis of the lens; a beam splitter operatively positioned on the focal axis of the focusing lens and positioned between the focal point of the focusing lens and the detector; a light source directed toward the beam splitter wherein the light source can impinge upon the beam splitter and be redirected by the beam splitter to follow the focal axis of the focusing lens to the focal point of the focusing lens; and a mask having an aperture, the mask operatively and adjustably positioned between the light source and the beam splitter so that the aperture can be adjusted with respect to a light beam from the light source and to define the size and shape of the light source; wherein the focal point of the lens can be positioned on a surface to determine the planar orientation of the surface.