Optical retrieval apparatus of the peekaboo type

Claim 1

OPTICAL APPARATUS FOR THE RETRIEVAL OF INFORMATION FROM RECORDS OF THE COORDINATE-INDEXED PEEKABOO TYPE, INCLUDING MEANS FOR HOLDING, IN SUPERPOSED ALIGNMENT, A PLURALITY OF GEOMETRICALLY IDENTICAL FLAT SHEETS EACH BEING GENERALLY OPAQUE BUT CARRYING A PATTERN OF LIGHTTRANSMITTING SPOTS ARRANGED AT SELECTIVE COLUMN-AND-ROW INTERSECTIONS OF A RECTANGULAR MATRIX COMMON TO ALL OF SAID CARDS, THE COINCIDENCE OF SUCH SPOTS AT IDENTICAL MATRIX POSITIONS OF ALL OF SAID SHEETS IDENTIFYING THE COORDINATE POSITIONS OF A LOGICAL FUNCTION OF THE SPOT PATTERNS OF ALL OF SAID SUPERPOSED SHEETS; A SCREEN; MEANS FOR PROJECTING LIGHT THROUGH SAID SUPERPOSED SHEETS TO ESTABLISH A PATTERN OF LIGHT BEAMS ON SAID SCREEN CORRESPONDING TO MATRIX POSITIONS OF SAID COINCIDING SPOTS; A MICROFILM SHEET CARRYING A MULTIPLICITY OF REDUCED-SIZE OPTICAL IMAGE RECORDS OF TEXT INFORMATION ARRANGED IN COLUMNS AND ROWS ACCORDING TO THE SAME RECTANGULAR MATRIX; OPTICAL ENLARGING MEANS FOR PROJECTING AN ENLARGED AND FOCUSED IMAGE OF ANY SELECTED ONE OF SAID IMAGE RECORDS ON SAID SCREEN FOR VIEWING THE SAME; AND MEANS MOUNTING SAID MICROFILM SHEET AND SAID OPTICAL ENLARGING MEANS FOR RELATIVE POSITIONAL ADJUSTMENT IN A PLANE PARALLEL TO THE PLANE OF SAID MICROFILM SHEET TO ACCOMPLISH SELECTION AND ENLARGED PROJECTION OF SAID ONE OF SAID IMAGE RECORDS; THE PATTERN OF LIGHT BEAMS PASSING THROUGH SAID SUPERPOSED SHEETS FORMING A POSITIONAL INDICATOR FOR SAID POSITIONAL ADJUSTMENT.