Apparatus for determining the position of a surface

摘要: This invention is directed to an electro-optical apparatus for determining the position of opaque surface without contact with surface. It includes a light beam system which projects well defined having rectangular cross-section, obliquely onto such that any movement in perpendicular direction will result displacement illuminated area on surface, and detector converts this into proportional intensity. The has field stop aperture specific shape imaged only portion image pass through depending area. A photosensitive device used measure intensity passing aperture. Embodiments normalizing output greater precision are described as measuring thickness object by two opposite surfaces object.