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In 1976 General_Scanning_Inc. and Intermedia_Systems_Corp. formed a new
joint venture called Interscan, located in Cambridge, Massachusetts. The purpose of the
new company was to produce custom laser displays for advertising, promotion, education,
entertainment, and industry. The systems offered ranged from small, self-contained
projectors to large permanent installations. The 1976 product brochure listed the
following prices:
The PCX-100 Skywriter, already developed by General_Scanning, was
Interscan's centerpiece. The core of the PCX-100 was known as a dedicated vector
generator. It stored in RAM a series of digital numbers A peculiarity of the vector generator was that successive data points could only be moved by a constant amount. In other words, all of the data points that made up a drawing were equally spaced. This caused the speed of the flying laser spot to be nearly constant, something very desirable when exposing laser lines on film, but not so important when the lines are to be viewed with the eye. The points were entered one at a time by pressing keys on a telephone-style keypad. The center key was not used. The eight outside keys represented eight directions, like the eight points on a compass. Despite being a limited and awkward way to make drawings, it was a great advance over previous systems. Once a drawing was created, it could be saved on the built-in Sony cassette recorder for later retrieval. Images produced by the Skywriter were static, but movement could be added by means of external inputs from oscillators, synthesizers, rotators, and the like. The Skywriter was packaged in a 21" x 15" x 14" rack mount box, with the laser and scanners at the end of a long cable. Next: Lovelight |
that represented the X and Y coordinates
of the image to be displayed. A clock circulated the coordinates in a continuous loop,
while outputting one X-Y pair at a time to digital-to-analog converters. An extra bit was
available for beam interrupt, or blanking. This was accomplished by using a third scanner
to rotate a small metal vane into the laser beam.