Flexible electronic circuits and displays

Abstract

A backplane for use in an electro-optic display comprises a patterned metal foil having a plurality of apertures extending therethrough, coated on at least side with an insulating polymeric material and having a plurality of thin film electronic devices provided on the insulating polymeric material.

Description

BACKGROUND OF INVENTIONThis invention relates to flexible electronic circuits and displays. More specifically, this invention relates to such circuits and displays using electro-optic media. This invention also relates to production of electro-optic displays on curved surfaces; these surfaces may be curved in one or both dimensions. This invention is especially but not exclusively concerned with electro-optic displays using encapsulated electrophoretic media.The term “electro-optic” as applied to a material or a display, is used herein in its conventional meaning in the imaging art to refer to a material having first and second display states differing in at least one optical property, the material being changed from its first to its second display state by application of an electric field to the material. Although the optical property is typically color perceptible to the human eye, it may be another optical property, such as optical transmission, reflectance, luminescence or, in t...

AI Technical Summary

Benefits of technology

This patent describes a backplane for an electro-optic display that includes a patterned metal foil with thin film electronic devices provided on the foil. The backplane may also have a conductive via extending through the polymeric material coating the metal foil. The invention also includes a process for driving the backplane and a process for forming a plurality of electronic components on a polymeric material coating a metal substrate. Additionally, this patent describes a stitchable display where the peripheral portion of the display can be stitched to a flexible medium. The invention also provides a process for forming an electro-optic display on a substrate curved in one dimension.

Problems solved by technology

Nevertheless, problems with the long-term image quality of these displays have prevented their widespread usage.

For example, particles that make up electrophoretic displays tend to settle, resulting in inadequate service-life for these displays.

However, stainless steel and similar metal foils do have the disadvantage that they are substantially denser than other potential substrate materials such as plastics.

It has been found that, if one attempts to form an encapsulated electrophoretic display on a curved surface by coating a layer of electrophoretic medium on a flat surface (as most traditional printing and similar coating processes require) and then deforming the layer of electrophoretic medium to the desired curved configuration, substantial damage to the electrophoretic medium may occur, depending upon the exact curved configuration required.

Such damage may include creep, which results in non-uniform switching of the electrophoretic medium, and / or rupture of some capsules, with resultant poor electro-optic performance, including reduction in contrast ratio and operating lifetime.

Similar problems may be experienced with other types of electro-optic media.

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