Browse Prior Art Database

Optical Tape Read Only Storage System

IP.com Disclosure Number: IPCOM000091756D
Original Publication Date: 1968-May-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 3 page(s) / 42K

Publishing Venue

IBM

Related People

Harris, TJ: AUTHOR

Abstract

Read-only storage for archival purposes is performed in this optical system. Random access is provided to any information byte on a storage frame.

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Optical Tape Read Only Storage System

Read-only storage for archival purposes is performed in this optical system. Random access is provided to any information byte on a storage frame.

Writing of information is effected on optical tape or film 1 carried by tape transport 2. Tape 1 is a transparent photographic emulsion. Light from arc lamp 3 is collimated by lens 4, polarized at 5, and provided to optical tree 6. Crystals in tree 6 are adjusted to select eight colors over a 400 Angstrom band. Each color provided by tree 6 is modulated by a bank of modulators 7 in accordance with input information supplied from buffer 8. A bank of filters 9, having a filter sensitive to each color, acts to absorb all other colors at the output of tree 6.

The eight beams modulated at 7 are recombined in tree 10. The multiwavelength beam provided by tree 10 is expanded by lenses 11 and 12. The latter focuses the beam through prism 13 and digital light deflector 14. Under the control of driver circuits 15, which are activated through register 16 by the input information from buffer 8, deflector 14 forms diffraction-limited spots at the output on film 1. Due to the dispersion introduced by prism 13, each color in the eight color beam is displaced by an amount equivalent to a spot diameter so that eight spots are formed on the film plane. Deflector 14 has the capacity for deflecting these eight spots across as well as down film 1.

Verification that the information is correctly written is accomplished by the bank of splitters 17 and photodetectors 18 on the opposite side of the film. All the information bits written on film 1 pass through it to lens 19. The latter collects the light and focuses it through the bank of splitters 17 to filters 20. Lenses 21 focus the filtered light on photodetectors 18...