Abstract: An optical apparatus for measuring angular or linear displacements. The apparatus comprises a single planar element having on its surface a pattern of sectors characterized by alternating optical transmission coefficients. An optical system superimposes a real image of a portion of the pattern upon that portion of the pattern itself. This image moves in the direction opposite to the planar element, so that as the element moves, the interaction of the sectors of the image with the sectors themselves creates alternating light and dark areas as a result of shuttering or interference effects. A light sensor monitors these light and dark areas thereby providing a measure of the displacement of the planar element.

Abstract: A sensory aid system for visually handicapped persons. The system provides a magnified image of graphical material, such as text. The system includes an image sensor which may include a lens assembly and photodiode detector array. The image sensor is coupled to a display array, with each detector array element having a one-to-one correspondence with one (or a group of) display array elements. The display array may be adjusted electronically to provide any degree of magnification simply by changing the number of elements in the array driven by the signal information. The display array elements may be red light emitting diodes (LED's). In this form, the present invention provides a magnified brightly illuminated red image of the black areas of print against a black, or dark, background, instead of the conventional text format of black print (information) on white paper (noise).

Abstract: The invention is a new telescopic optical system that comprises an entrance pupil, a main mirror in the form of a truncated corner reflector disposed so that its base faces said entrance pupil, and a secondary mirror, said mirror being arranged so that said main mirror receives light admitted by said entrance pupil and reflects it back to said secondary mirror and said secondary mirror reflects said same light back through the truncated section of said main mirror.