Browse Prior Art Database

Thermosensitive Display With Improved Operational Characteristics

IP.com Disclosure Number: IPCOM000053024D
Original Publication Date: 1981-Aug-01
Included in the Prior Art Database: 2005-Feb-12
Document File: 3 page(s) / 26K

Publishing Venue

IBM

Related People

Pennington, KS: AUTHOR

Abstract

A class of thermosensitive display devices is disclosed herein and, in particular, thermosensitive displays similar to those described in [*]. The display disclosed in [*] employs a thermosensitive material, such as silver mercuric iodide (Ag(2)HgI(4)) deposited on a polymer and overlayed with another protective sheet of polymer. The display material disclosed in [*] also has white backing layers for improved visual and illumination means.

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Thermosensitive Display With Improved Operational Characteristics

A class of thermosensitive display devices is disclosed herein and, in particular, thermosensitive displays similar to those described in [*]. The display disclosed in [*] employs a thermosensitive material, such as silver mercuric iodide (Ag(2)HgI(4)) deposited on a polymer and overlayed with another protective sheet of polymer. The display material disclosed in [*] also has white backing layers for improved visual and illumination means.

The display is written by means of a thermal resistive head which consists of an array of thin film resistors together with on-head logic and drivers.

The improved structure and display driving means described herein offer increased resolution, hence quality, decreased writing energy, and reduced costs associated with the writing head. Also, the technique described herein will allow increased writing speed for the display should that be necessary.

Referring to the figure, a thermosensitive material layer 2, such as silver mercuric iodide, is deposited on an electrically resistive polymer A, such as Kapton, loaded with conductive graphite or similar heat-stable polymers which are made conducting or resistive by loading them with conductive materials, such as graphite, zinc, etc. The resistive polymer would be embossed on one side and then coated with a thin film 6 of aluminum (250-1000 angstroms thick). This will provide for an electrical return path as well as providing a diffuse reflective surface which appears white. The thermosensitive material 2 is then coated onto the aluminum layer, and finally the thermosensitive layer 2 is coated with a transparent protective coating 8, such as a polyester.

The display is then addressed via an array of contacting electrical styli 10. As any of the contacting styli are addressed by a voltage and current source, the localized flow of current into the resistive substrate 2 produces local heating, as will be understood by those skilled in the art. This local heating produces a color change in the thermosensitive medium. As long as the substrate temperatur...