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Readout from Thermoplastic Record Element

IP.com Disclosure Number: IPCOM000092400D
Original Publication Date: 1967-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Fleisher, H: AUTHOR [+2]

Abstract

The information storage density of thermoplastic materials is increased by using a small concave depression in the material rather than the conventional larger grating-like bit. Precisely constructed and registered aperture plates are eliminated from the readout system. Bit detection is accomplished by using the wavelength angle variation of an interference filter to pass light from one type of stored binary information and to block the light from the other type of binary information.

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Readout from Thermoplastic Record Element

The information storage density of thermoplastic materials is increased by using a small concave depression in the material rather than the conventional larger grating-like bit. Precisely constructed and registered aperture plates are eliminated from the readout system. Bit detection is accomplished by using the wavelength angle variation of an interference filter to pass light from one type of stored binary information and to block the light from the other type of binary information.

A deformation in the thermoplastic material acts as a concave lens to diverge the light in a collimated beam. The diverging light is incident on an interference filter and passes through the filter, if the angle theta at which the light strikes the filter is related to the wavelength of peak transmission lambda o of the filter and the laser wavelength lambda by

(Image Omitted)

where n = the refractive index of the filter. If the illuminating laser wavelength is shorter than the peak transmitted wavelength of the interference filter, some of the diverging light from a deformation in the thermoplastic material is passed by the filter. The light passing through an undeformed area is not deviated and passed by the filter.

Thermoplastic memory element 1 is illuminated by collimated laser beam 2. Element 1 has deformation areas 3 where information is stored. Deformations 3 have the form of concave spherical lenses. Light 4 passed by areas 3 having...