Thermoplastic image recording system

Abstract

Abstract Erasable thermoplastic image recording systems having extended useful lifetimes are provided by subjecting the thermoplastic recording medium to a sequence of erasure, exposure to incident radiation cooling and projection in an inert atmosphere while applying corona charge throughout the erasure and exposure cycles. By exposing at a time when the medium is cooling from the erasure step, a heat development step is eliminated which eliminates nearly 50% of the thermal degradation of the thermoplastic polymer. Exclusion of oxygen from the system eliminates the considerable chemical degradation the film suffers from reaction with ozone. Erasure in the presence of a uniform corona charge provides more complete erasure than standard procedures. Lower temperature and shorter heating pulses are permitted with a lower surface tension thermoplastic polymer provided by external plastization of the thermoplastic. The lower surface tension also results in less noisy images and greater lifetimes. Compared to existing art, the system is significantly simplified, less expensive to construct and operate, and further provides faster recycling of the recording media as one heating cycle and one cooling cycle are aliminated. The system is adaptable to a recyclable storage system for holographic movies in which frames of the media are applied near the circumference of a rigid disc substrate and a motor sequences the frames through the steps of erasure, exposure and projection such that all steps take place at the same time but on different portions of the disc. The system is particularly useful for projection of acoustic holograms which cannot be viewed directly by conventional optics.

Inventors

• 👤 John E. Wreede
• 👤 Terence C. Stoddard
• 👤 Kenneth R. Erikson

Bibliographic Details