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Thin Films for Image Storage

IP.com Disclosure Number: IPCOM000079407D
Original Publication Date: 1973-Jun-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 14K

Publishing Venue

IBM

Related People

Gambino, RJ: AUTHOR [+2]

Abstract

There are described herein materials which are advantageously employed for reversible image storage. These materials are evaporated amorphous films of MoO(3) and WO(3) and darken on exposure to ultraviolet or visible light of moderate intensity (1 to 10 watts/cm/2/). The change in the absorption constant, delta alpha, is typically about 500 cm/-1/. An image can be replicated on these films by their exposure through a photographic negative or a metal mask, and the image which is thereby produced can be bleached by heating the film or by exposure of the film to a corona discharge in air, i.e., an electric field of approximately 10,000 volts/cm.

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Thin Films for Image Storage

There are described herein materials which are advantageously employed for reversible image storage. These materials are evaporated amorphous films of MoO(3) and WO(3) and darken on exposure to ultraviolet or visible light of moderate intensity (1 to 10 watts/cm/2/). The change in the absorption constant, delta alpha, is typically about 500 cm/-1/. An image can be replicated on these films by their exposure through a photographic negative or a metal mask, and the image which is thereby produced can be bleached by heating the film or by exposure of the film to a corona discharge in air, i.e., an electric field of approximately 10,000 volts/cm.

The exposed and unexposed regions can be decorated with aerosol droplets in a manner similar to that used for decorating ferroelectric domains (dew method), thereby demonstrating that there is an electric-field gradient between the exposed and the unexposed regions. It has been found that the exposed and unexposed regions also show a differential etch rate in water or ammonia vapor. The etching method can be employed to enhance and fix the image. When carefully controlled, it has been found that the differential etching renders these films useful as inorganic photoresists. In addition, the capability of depositing these materials as thin, uniform, continuous films renders them particularly suitable for high-resolution electron-beam lithography. The aforementioned differential etching can also be employed for printing applications. In this connection, the MoO(3) layer on a molybdenum drum is exposed, etched and inked. After these steps, the drum is now capable of receiving new copy by the etching off of all of the oxide, forming a new oxide layer by anodization or thermal oxidation and exposing to a new image.

The darkening process consists of photogeneration of carriers which become trapped at the color center sites. The other effects, as mentioned hereinabove, are associated with the electrostrictive nature of the...