Other

Terminal Data Corporation

William R Limburg

Jay Smith, Iii

John S Burton

Robert A Nordmeyer

James E Headley

William C Turner

An optical film reader for projecting and enlarging micro copy information recorded in rollfiche format on rolls of photographic film or the like which provides a film transport mechanism enabling rapid manual scanning of the enclosed rollfiche strip in both directions, with instantaneous reversal of the scanning direction without backlash in the film drive. A low glare, high contrast viewing screen is mounted at 45.degree. to the vertical and placed low at the front of the unit perpendicular to the viewer's line of sight. Movable projection optics are provided for scanning of rollfiche microcopy which is wider than that projectable on a fixed sized screen at one given time at a given magnification ratio; the movable projection optics allow projection of the micro copy data or eye-readable index area of the rollfiche by means of a single scanning lever.

Optical rollfiche reader

A photographic exposure control for sensing and electrically processing illumination reflected from a moving document. An opto-photoelectric pickup accepts reflected illumination having a selected spectral characteristic. Electronic analog logic; (1) samples and holds the equivalent electrical magnitude of the reflected illumination, (2) provides an electrical timing interval that is the reciprocal of the electrical magnitude, (3) arranges automatically for constant exposure of the film through an adjustable electrical ramp generator, and (4) generates an 'exposure stop' signal in a comparator that receives the ramp and the reciprocal timing information. The control signal thereby formulated typically accurately actuates a translational type shutter through a stepper motor to maintain a constant density of the background of images on microfilm for successive documents regardless of the background reflectivity thereof. A 'Manual' mode is alternately available for providing a fixed exposure, particularly for documents having unorthodox reflectivity formats.

Electronic exposure control

Growing community of inventors

Torrance, CA, United States of America

William R Limburg