| 摘要 |
1,199,529. Photo-electric control of data displays. INTERNATIONAL BUSINESS MACHINES CORP. Nov.29, 1968 [Jan.12, 1968], No.56893/68. Heading G1A. A display system comprises means for illuminating a display screen with a light image linearly polarized in a first direction, means for directing on to an area of said screen a light beam linearly polarized in a second direction and polarizationsensitive means responsive to the coincidence of both said image and said light beam in said area for producing an optical control signal. Alphanumeric characters are selected from a matrix under computer control as described in U.S. Patent No. RE. 26,170 and deflected to desired points on a display screen 20 by a computer controlled deflector 14. The character is transmitted in plane polarized light and in order to indicate to the computer a particular point 28 on the display an operator directs a beam of orthogonally polarized light 24 at the point. Reflected and transmitted light from the point 28 is deflected by a beamsplitter 16 to an optical AND gate 42 of the type disclosed in Specification 1,199,530 which gives out light through analyzer 58 only when the beams 10 and 24 are directed to the same point on the display screen. A photo-detector 62 picks-up the optical control pulse to effect erasure of a character from memory 32 or writing in of a character keyed in at 66. |
